More than 100 wives and partners of police have protested in Paris against attacks on police following the killing of an officer on the Champs Elysees.
The Angry Police Wives group marched through the city two days after Xavier Jugelé was shot twice in the head by convicted criminal Karim Cheurfi.
Separately, police fired tear gas amid confrontations after a trade union demonstration in eastern Paris calling for a "social first round" of voting.
France goes to the polls on Sunday.
In another incident, French media said a man with a knife had been arrested at the Gare du Nord station. Police have not said if the incident is terrorism-related.
Candidates in the presidential election have been accused of exploiting the Champs Elysees attack politically.
Two other officers were wounded before Cheurfi was shot dead.
The killer had spoken about wanting to kill police but had had no apparent link to Islamist radicalism before the attack, prosecutors said. A note defending so-called Islamic State (IS) was found near his body.
At the end of the pro-police demonstration, marchers released black balloons signifying police killed in the line of duty and pink balloons for the families they left behind.
Some were carrying placards saying "don't touch my cop", a twist on a well-known French anti-racism slogan.
One placard also said "enough police officers killed and burned", referring not only to Mr Jugele's death but also a firebomb attack on a police car carrying four officers by suspected drug dealers in a poor suburb of Paris last October.
Two of the officers were seriously wounded in the attack.
Police officers have also been hurt in recent protests over allegations of police brutality.
Who was the victim?
Police officer Xavier Jugelé, 37, was an active campaigner for gay rights, French media report. He was in a civil partnership and did not have children.
Originally from the Loire Valley region in central France, he had been serving in the capital since 2014, French daily Liberation writes (in French).
He was deployed on the night of the November 2015 attacks in Paris to the Bataclan concert hall, returning the following year on the night the venue reopened.
The BBC's Nick Garnett interviewed him at the time. "I want to celebrate life and say 'no' to terrorism," he told our reporter.
Recent terror attacks in France
- 7-9 Jan 2015 - Two Islamist gunmen storm the Paris offices of satirical magazine Charlie Hebdo, killing 17 people. Another Islamist militant kills a policewoman the next day and takes hostages at a Jewish supermarket in Paris. Four hostages are killed before police shoot the gunman dead. The other two gunmen are cornered and killed by police in a siege.
- 13 Nov 2015 - IS jihadists armed with bombs and assault rifles attack Paris, targeting the national stadium, cafes and Bataclan concert hall. The co-ordinated assault leaves 130 people dead, and more than 350 wounded.
- 13 Jun 2016 -A knife-wielding jihadist kills a police officer and his partner at their home in Magnanville, west of Paris. He declares allegiance to IS, and police later kill him.
- 14 Jul 2016 - A huge lorry mows down a crowd of people on the Nice beachfront during Bastille Day celebrations, killing 86. IS claims the attack - by a Tunisian-born driver, later shot dead by police.
- 26 Jul 2016 - Two attackers slits the throat of a priest at his church in Saint-Etienne-du-Rouvray, in Normandy. They are shot dead by police.
- 3 Feb 2017 - A machete-wielding Egyptian man shouting "Allahu akbar" attacks French soldiers at Paris's Louvre Museum - he is shot and wounded.
- 20 Apr 2017 - A convicted criminal who was investigated for threatening to kill police opens fire at police on the Champs Elysees in Paris, killing one and wounding two. He is shot dead - and the assault is claimed by IS.
You can follow the first round of the French election on the BBC News website. Click here for all our latest coverage. On the day of the election, we will be running a live page bringing together the latest news, video and analysis.
On TV, you can watch a BBC World News Election Special, from 18:30 BST (17:30 GMT / 19:30 local time in France) on Sunday, which will be broadcast on BBC News in the UK and on BBC World News internationally, with Christian Fraser presenting from Paris.
For radio, BBC World Service will broadcast a special extended edition of Newshour from Paris at 18:00 GMT on Sunday.