Rally at Paris mosque against Herve Gourdel killers
Hundreds of people have taken part in a protest led by France's leading Muslim cleric against the beheading of a French hostage by jihadists in Algeria.
Dalil Boubakeur, head of the French Council of the Muslim Faith, told the crowd outside the main Paris mosque that the killers had no claim to Islam.
He said French Muslims were united against "barbarism".
Herve Gourdel, was killed by militants allied to Islamic State (IS) while on holiday in Algeria's Kabylie region.
The mountain guide was kidnapped by the Jund al-Khalifa group last Sunday.
The militants initially released a video of the hostage, giving France an ultimatum to halt air strikes on IS in Iraq. On Wednesday, they beheaded Mr Gourdel after claiming that their deadline had run out.
Three days of national mourning are being observed until Sunday, with flags being flown at half mast across France.
Religious and political leaders attended Friday's rally in Paris, joining Muslims who had just finished Friday prayers.
Mr Boubakeur praised the gathering as a "strong and vibrant expression" of the "desire for national unity and unwavering will to live together".
Similar demonstrations took place in other French cities.
The BBC's Hugh Schofield in Paris says some Muslim activists have criticised such rallies, arguing that they suggest Muslims have something to apologise for. But others have said they are an instinctive act of solidarity.
French President Francois Hollande condemned the killing as "cruel and cowardly", and said the air strikes in Iraq would continue.
He has also called for security to be boosted on public transport and around public buildings in Paris.