WASHINGTON (AFP) - US lawmakers are set to pay tribute to the victims of the Paris attacks by holding up pencils during President Barack Obama's State of the Union speech on Tuesday.

Democrat representative Gwen Moore's office said the legislator will hold up a yellow pencil during the applause break to honour those who lost their lives in the attacks.

Others other lawmakers may follow suit, Ms Moore's office added.

Referencing how the pencil has become a global symbol of free speech in the wake of the brutal attack on the French satirical magazine Charlie Hebdo, Ms Moore's office called the planned event a "unique opportunity to join our global partners in showing our collective support and solidarity".

Crowds in several cities have taken to raising pencils skyward in memory of those killed at the magazine, several of whom were well-known cartoonists.

Ms Moore is a six-term House Democrat from Wisconsin.