PARIS (AFP) - President Francois Hollande on Wednesday (Nov 25) called on French citizens to deck their homes with the national flag during a day of mourning later this week for victims of the Paris attacks.

Friday will be a day of homage to the 130 people killed by extremists in the Nov 13 assaults, and the president urged citizens "to participate by decorating their homes with the blue, white and red flag," government spokesman Stephane Le Foll said.

Hollande will lead a solemn ceremony on Friday commemorating the victims of France's worst-ever terror attack at the Invalides, the grand complex in central Paris that houses a military museum and Napoleon's tomb.

The event, to be attended by victims' families and those wounded in the attacks and described as "the most solemn, the most republican that could be chosen" will include a speech by Hollande.

Displaying national flags at home is not common in France, but Le Foll said the attacks had "touched every one of our fellow citizens very deeply" and the president wanted people to be able to join in with the memorial service.

"We have tried to suggest something that will let every French person take part in Friday's ceremony," he said.

Sales of the "tricolore" have boomed since the attacks, with leading flag-maker Doublet saying it had moved "between two and three times as many French flags as usual".

The flag has become an emblem of defiance after the Paris carnage, flourishing at the sites of the attacks attached to flowers, pictures and other tributes as well as on social media, where Facebook has given users the chance to add a red, white and blue filter to their profile pictures.

Sandra Laugier, a philosophy lecturer at the Sorbonne University, said that after years in which the tricolore was seen by many as a symbol of belligerent nationalism, it had now become a banner for "the love of life", as opposed to the Islamic State in Iraq and Syria group's "love of death" and black flag.