By Brian Love
PARIS (Reuters) - French riot police used tear gas and water cannon to clear stone-hurling youths as unions kicked off a fresh wave of street protests and strikes on Tuesday over planned labour reforms, but President Francois Hollande refused to back down.
Truckers blocked access roads to fuel and food supply depots and rail workers went on strike in a week that has been billed by French media as make-or-break for a months-long protest movement that has recently shown signs of losing momentum.
Hollande, whose popularity is at rock bottom a year before a presidential election, said he would not scrap changes to one of Europe's most protective labour laws -- a flagship reform that would make hiring and firing easier.
"I will not give in," the 61-year-old Socialist leader told Europe 1 radio.
Armed police evacuated a FNAC consumer goods store in Nantes targeted by troublemakers.
Members of the hardline CGT union used cement and concrete blocks to shutter up the window of a Socialist Party office in the southern city of Toulouse, and riot police engaged in cat-and-mouse chases with masked and hooded groups in Lyon, Marseille and the capital. Police reported 75 arrests.
The truckers slowed or blocked traffic on major roads and at strategic junctions, notably in the Bordeaux region of southwestern France, where they turned away deliveries to a supermarket and fuel supply hubs.
CGT chief Philippe Martinez led the Paris march, which like others across the country was joined by backers of the Nuit Debout protest movement (which loosely translates as "Night Uprising") that sprang up in response to the labour reforms.
The SNCF railway operator predicted sharp cuts in regional, intercity and high-speed services due to a strike that began on Tuesday evening and is set to run until Friday, with the CGT and another union planning similar stoppages in the weeks to come.
Hollande said 1,000 people had been arrested and more than 300 police injured during the clashes of recent months and said some troublemakers from outside the country were involved.
"People have a right to protest, but rioting is an offence that will be punished," he said.
The Interior Ministry said some 68,000 people took part in Tuesday's marches, compared to a tally of 55,000 for a May 12 protest -- both sharply down from an estimated 390,000 who turned out at the end of March.
The CGT and smaller unions have called rolling strikes by dockers and airport staff in addition to the rail stoppages and a further nationwide street protest on Thursday. France's DGAC aviation authority warned of disruption at many airports and a 15 percent cut in services at Paris Orly on Thursday.
At Total's 219,000 barrels-per-day Donges refinery in western France, CGT official Christophe Hiou said "not a drop" of oil or fuel was entering or leaving the facility. Workers are considering further action in coming days, he said.
Salaried truckers say they will be among the first to suffer under the new law, which would allow road haulage firms to back out of overtime pay deals that often account for thousands of euros of a driver's annual pay packet.
(With additional reporting by Claude Cannelas in Bordeaux, Jean-Francois Rosnoblet in Marseille, Julie Rimbert in Toulouse and Guillaume Frouin in Nantes; Editing by Laurence Frost and Gareth Jones)