After several days of clashes between police and youths during demonstrations against police brutality, bus shelters and dustbins were burnt and police made eight arrests in the Normandy city on Friday evening.
After about 150 people, according to police, rallied near a metro and tram station, a group of youths ignored appeals to remain calm from far-left activists and clashed with police, who used teargas to disperse them.
A larger march in the western city of Nantes went off peacefully.
Antiracist campaigners and left-wing unions called a demonstration in Paris on Saturday and similar rallies were planned in other parts of the country.
The authorities have tightened restrictions on the sale of alcohol and drinks in glass bottles in the area where the Paris protests is to take place.
Le Pen calls for demo ban
Far-right presidential candidate Marine Le Pen called for the demonstrations to be banned, claiming that they would give rise to slogans insulting to the police and the nation and posed a threat to public order.
Pointing out that the state of emergency declared after the November 2015 Paris attacks is still in place, she declared it "incomprehensible that the government has not taken the necessary measures".
"They must put a stop to the ultraviolent, extreme-left militias to which the government shows a great indulgence," she said in a statement on Saturday. "It would also be the occasion to stop the chanting of vile slogans insulting the whole police force and insulting France."
Théo leaves hospital
Théo Luhaka, the victim of alleged rape with an extendable baton by a police officer, left hospital on Thursday two weeks after the incident.
Interior Minister Bruno Le Roux wished him a speedy recovery on Friday and insisted that the law would take its course.
The police officer has been charged with rape and he and his colleagues have been suspended.
The police "must be the first to defend the values of the republic and, if I judge that they are not doing so, there will be penalties", he said.