A week after the terrorist attacks in France last November, Bachir B., a passenger screener at Orly airport south of Paris, was called into his manager's office. Bachir, a devout Muslim who wears a thick beard in keeping with his faith, was ordered to trim his facial hair. His boss even offered to buy him a beard clipper as a birthday gift.

While supervisors had sometimes reminded Bachir of a company dress code requiring whiskers to be kept "tidy" and "short", Bachir said that the rule had been enforced only sporadically over his six years working for Securitas, a private security company. This time, the manager made it clear that the new crackdown was "because of what was happening in the news", said Bachir, who asked that his last name not be used to protect his family's privacy.

Bachir trimmed his beard that weekend. But he said his boss sent him home about 10 days later, again citing his failure to comply with the dress code. Soon after, Bachir received a registered letter from Securitas, saying that he was fired.

Reconciling the religious precepts of observant Muslims with the secular norms in the European workplace has long been a sensitive subject. France's strict legal separation of religious and civic life - a legacy of the French Revolution known as laicite (pronounced lie-ee-see-tay) - formally discourages and, in some situations, expressly bans public religious expression. It is a brand of secularism that coexists uneasily with Islamic traditions, making workplace negotiations about religious practice particularly difficult and prone to misunderstandings.

The issues have become thornier after the latest wave of terrorist activity, including the November attacks in Paris that left 130 dead.

With much of the region on edge, the French government has set a forceful tone, granting sweeping emergency powers to the police and stepping up the scrutiny of mosques, Islamic associations and individuals. The sense of unease is particularly palpable for companies operating in sensitive areas like transportation, security and infrastructure.

Adding to workplace conflicts like the one at Securitas, as well as reports of tensions at other large employers, is that many Muslims have become more assertive in fighting stigmatisation on the job.

But many managers and union leaders in France report feeling ill-equipped to respond to employee demands for things like dedicated prayer rooms or pork-free canteens - let alone to detect and combat genuine radicalisation at work.

"Today, we are in a very complicated situation," said Mr Philippe Humeau, a researcher at InAgora, a consultancy that specialises in religion and the workplace.

While France's workplace rules around religion are relatively distinct, the broad concerns are playing out globally, as countries confront the rise in terrorist activities.

In the United States, questions of workplace safety arose after a radicalised California health department employee killed 14 colleagues in an attack on an office party in San Bernardino, California, in December.

"Most companies don't know much about Islam," he said. And in the current climate, "we are seeing companies confuse strict religious practice, which is already difficult to accept in France, with radicalisation". The risk is that companies, in a quest to protect their staff and their clients, unfairly profile certain employees.

Bachir is convinced that he was fired over fears that his religious expression made him a possible security threat. He filed a discrimination complaint against Securitas with French prosecutors, who are reviewing it.

He is one of at least a half-dozen security guards - all bearded Muslim men - who have been let go by Securitas since the November attacks. They are all challenging their dismissals in a French labour court.

Their dismissals followed a similar pattern. In late November, they received the same written warning, copies of which were reviewed by The New York Times. "The face must be close-shaven, goatees, moustaches and beards kept short, trimmed, tidy and maintained," the warnings stated. Weeks later, they were sent dismissal letters. The letters refer to repeated violations of the dress code while a few, including Bachir's letter, also list additional infractions, such as unexcused absences and tardiness.

"That beard did not just grow from one day to the next," said Mr Eric Moutet, a lawyer representing the men. "But suddenly now, it's a problem? Clearly it's not something about his behaviour that has changed, but rather it is the way that person is now being viewed."

Securitas - which provides about 400 security agents to Orly airport under a multi-year contract, and an additional 1,000 at Charles de Gaulle airport in Paris - declined to discuss the specific dismissals, citing the pending litigation. The security company said the beard rules and the subsequent firings adhered to the law. As a private company working on behalf of public-sector clients like the airport, Securitas said it must conform to France's strict secularism laws.

"We are confident," Mr Michel Mathieu, the head of Securitas' French operations, said, in reference to the decision to fire the Orly guards. The company has not accused the guards of any illegal activities, nor has it presented any evidence that they engaged in radical behaviour on the job. But he said that recent events had led Securitas to revisit its approach to all forms of religious practice in the workplace.

What some might view as overt religious profiling, Mr Mathieu insisted had become a necessity for a company like Securitas, whose mission is to protect against potential dangers that now include Islamist terrorism. The risks, he added, were no longer abstract. Last year, Securitas alerted the French authorities to four security agents who, despite a rigorous vetting process that includes multiple background checks, were found in possession of Islamist propaganda on the job.

In the days after the deadly November attacks, it emerged that one of the gunmen identified in the attack at the Bataclan concert hall had once worked as a bus driver for RATP, the Paris transportation authority. Almost immediately, the French media questioned whether more radical Islamists might be lurking among the RATP's staff. Some labour union leaders complained that managers, fearful of complaints from Muslim employees, had long tolerated religious behaviour on the job that was explicitly prohibited by the company's own policies.

The RATP chief executive, Ms Elisabeth Borne, swiftly dismissed the speculation as overblown and warned against "conflating" religious practice with extremism. But the company also quietly acknowledged that workplace conflicts linked to religious behaviour, albeit still "very marginal" in number, had become a concern in recent years.

Officially, France's vigorous brand of secularism applies to all religious faiths. But over the last decade, regulations on laicite have tended to focus on Islam. A law prohibiting government employees and high-school students from wearing headscarves and other "conspicuous" religious attire was introduced in 2004. A specific prohibition against women wearing full-face veils in public went into effect in 2011.

Opinion polls show such bans have broad public support - and they have been upheld recently by Europe's top human-rights court. But they are resented by many of France's five million Muslims who see the rules as unfairly stigmatising their religion.

The principle of laicite, however, applies only to those who work in France's vast public-sector economy. For private companies like Securitas, the situation is murkier.

FEAR OF INFILTRATION

Under French labour law, private employers are required to respect the religious freedom of their employees, meaning that such companies are expected to tolerate religion on the job. Only proselytising and acts of pressure towards other employees are expressly banned.

The regulations do, however, allow for a number of exceptions, like employee health and safety, operational continuity and protecting commercial interests. And private companies working in the public arena create a grey area.

In strict practice, the rules mean that an employee who accepts a job at a butcher shop, for example, cannot refuse to handle pork. A train driver would not be allowed to stop on the tracks to pray. A waitress cannot decline to serve alcohol to customers. But many situations are less clear cut.

Ms Fatima Afif had worn her headscarf for close to a decade as an employee of Baby-Loup, a daycare centre in a working-class suburb of Paris. But when she returned to work in 2008 after an extended parental leave, she was ordered to take it off.

The nursery, owned by a private association that catered to single and working mothers, argued that it needed to be religiously neutral in order to serve a large immigrant community that had become increasingly diverse. When Ms Afif refused to comply, she was fired.

The case eventually became a cause celebre, pitting civil rights groups and Islamic activists against an unlikely coalition of secularists, feminists and politicians on the far right. The French courts struggled to reach a consistent verdict.

An initial ruling in 2011 supported the daycare centre, saying that although it was private, it was effectively providing a public service that should be religiously neutral. But that decision was reversed in early 2013 by a higher court, only to be overturned again six months later by the Paris Court of Appeal on the grounds that a veiled employee might drive away certain clients, causing commercial harm.

The courts' flip-flops over the Baby-Loup case "left people more uncertain about the legal framework", said Mr Guy Trolliet, a job coach and consultant on intercultural and religious affairs.

Employers indicate that conflicts over religion in the workplace are on the rise. A survey last year of 1,300 French companies by the Observatory of Workplace Religious Practice, a research group based at the Institute of Political Science in Rennes, France, found that 12 per cent of human resource managers had faced disputes over religious practices that were difficult to resolve, up from 6 per cent in 2013.

Among the most difficult situations cited included employees' rejection of the company's authority to set limits on religious behaviour, as well as refusals by some men to work alongside women, either as a colleague or a boss.

But the legal issues, as well as the political and social implications, have left many companies - private and state-owned - unsure as to how to proceed. That uncertainty has resulted in an ad hoc approach that is rife with potential problems, both for companies and their staff members.

Some employers complain that they have limited means with French law to try to determine whether the religious behaviour of specific employees should be a legitimate cause for concern.

While the country's intelligence services maintain a list of around 10,000 people with known or suspected links to radical Islamist groups, privacy laws prevent law enforcement agencies from sharing those names with employers.

Mr Gilles Leclair, head of security for Air France, told a French parliamentary committee last spring that the airline was particularly sensitive to the threat of infiltration by radical groups.

"But legally, we can't force employees to inform us" about troubling behaviour, he said, and individuals were often able to successfully challenge such dismissals in French labour courts. "It's all well and good to detect radical phenomena, but we also need the legal means" to respond, Mr Leclair said.

Mr Guillaume Pepy, the head of SNCF, the French national railway operator, recently conceded that the country's anti-terrorist services had alerted the company - which employs 50,000 people - to as many as 10 employees in the last year whom they suspected of having ties to Islamist groups. But rather than fire the employees and risk a costly discrimination suit, Mr Pepy told a French radio last month that it was SNCF's policy to ensure that the individuals were not allowed to be train drivers or signal operators or to hold other positions that could pose a security threat.

"We don't fire them because that could be a powerful incitement to radicalisation," Mr Pepy said.

Analysts said most companies were able to deal with more common employee requests - including the ability to wear headscarves or arrange schedules and break times to allow for prayers and other observances - and that those actions could be easily distinguished from proselytising or abrupt changes in behaviour that could be a sign of radicalisation.

But those lines are not always discernible, and some people, like the job coach Trolliet, worry that the current environment of fear could quickly erode employers' openness to religious accommodation in general. "As always," he said, "there are groups that have a hidden agenda, who will use the leverage of well-meaning people."

DEALING WITH RADICALS

Because they work for a public entity, employees of the RATP are expressly prohibited from "any behaviour or wearing of conspicuous signs that could reveal an affiliation with any religion or philosophy whatsoever". Violations of this rule will subject a staff member to disciplinary action, including potential termination.

So when Mr Christophe Salmon, a delegate for CFDT, a leading French labour union, started receiving complaints about a group of male bus drivers who were refusing to address female colleagues or shake their hands, he raised the alarm.

At certain bus depots, he said, some male employees would not take the wheel of a vehicle that had been previously driven by a woman.

Rather than report the behaviour to the authority's human resource managers, Mr Salmon said that supervisors simply adjusted the drivers' schedules and routes to avoid handoffs between women and men. In one case, Mr Salmon said, a woman, who lived within walking distance of her depot, asked to be transferred to a job across town, rather than stay and continue to endure the harassment.

Some of the drivers were ultimately reprimanded, but none was fired, an outcome that Mr Salmon said amounted to "a kind of trivialisation" of such behaviour. The authority responded by distributing a 34-page handbook in 2013 that defines the principles of religious neutrality and diversity to managers. The handbook describes a number of common workplace situations. However, Mr Salmon said, few supervisors received formal practical guidance on how to address conflicts when they arose.

"These guys have been very well-trained to drive buses and trains, but they know nothing about laicite," Mr Salmon said, referring to the supervisors. "All they have is a bunch of guidelines on paper."

In an e-mailed statement, the Paris transport authority said it took questions of religious conflict "seriously", although it declined to discuss specific cases. The company recently announced the creation of a new working group, reporting to the chief executive, that was intended to provide "concrete support to front-line managers" on questions of religious behaviour.

In addition, plans are in the works to develop a dedicated peer-support network, giving staff members a resource for informal advice when issues arise.

Uncertain about the true security threats to their operations and staff, many employers are now struggling to strike an appropriate balance between vigilance and protection of the rights of their employees. "That is the real trap for employers," said Mr Lionel Honore, director of the Observatory of Workplace Religious Practice.

Paradoxically, he said, it is often the employees most open to dialogue who are the first to be pressed to adapt their religious practices, while more troubling behaviour is sometimes allowed to continue unchallenged for fear of escalating the problem.

"Radical people make some managers nervous, and so they leave them alone," Mr Honore said.

At Securitas, Mr Mathieu conceded that the company's crackdown on beards and other forms of religious expression had raised concerns among staff members, and not only among Muslims. He said that the company was sensitive to the risk of making "errors of good faith" about religious behaviour on the job. "People can confuse these things, either voluntarily or involuntarily," Mr Mathieu said. "I always want to make things as transparent as possible."

Mr Moutet, the lawyer for the Securitas guards, said the number of dismissed Muslim workers who had contacted him to bring religious discrimination suits has been rising over the last year. That increase, he feared, was in line with the tougher stance against terrorism being taken by the French authorities.

"It seems that there are some companies that are taking advantage of the mood of panic to try to clean house and sweep out certain people that they simply don't like," Mr Moutet said.

Bachir, the former Orly guard whose beard cost him his job, worries that cases like his will become more common. He still maintains a valid security guard's licence, which is granted only after an extensive police background check. But Bachir, who is married and is a father, said he was considering a new line of work or even going into business for himself.

"Today in France, laicite has only one meaning, and it is anti-Islam," he said. "It has become so widespread. And now, yes, it has infected the workplace."

NEW YORK TIMES