Mantes-la-Jolie - About 2 500 people marched in silence on Thursday in honour of a policeman and his partner who were knifed to death by an extremist pledging allegiance to the Islamic State group.
Many in the crowd of police, gendarmes, firefighters and locals wept as they walked from the police station where the couple worked in the Paris suburb of Mantes-la-Jolie to their home in Magnanville where they were killed on Monday.
The attack came in the midst of the Euro football championship - already dogged by terror fears - and is the first since Islamic State gunmen and suicide bombers struck Paris in November, killing 130.
"I don't feel a form of fear, rather disappointment," said Alain, the head of a Parisian police unit who has told his officers to "be careful - we have to change our behaviour."
In Monday's assault, 25-year-old Larossi Abballa, previously convicted for jihadism, killed 42-year-old police commander Jean-Baptiste Salvaing outside his home in Magnanville.
He then entered the house, taking Salvaing's 36-year-old partner Jessica Schneider and the couple's three-year-old son hostage, before slitting her throat.
Schneider was an employee of the police station where her partner worked.
Abballa was later killed in a police raid on the house, where officers found the little boy traumatised but unhurt.
Just before the raid, Abballa streamed a live video on Facebook of himself inside the house with the toddler, urging "other surprises" and pledging to "turn the Euro into a graveyard".
Paris prosecutor Francois Molins said police had found a hit list at the scene of the attack naming police, rappers and journalists.
Abballa, from Mantes-la-Jolie, told police negotiators before his death that he had sworn loyalty to ISIS three weeks earlier.
Three associates of Abballa have been arrested over the attack, two of whom were convicted alongside him in 2013 over ties to a network recruiting jihadists for Pakistan.
At the time, Abballa was sentenced to three years in prison.