French youths set off smoke bombs and scuffled with police on Thursday as they protested against proposed labour reforms, despite government climb-downs on the contentious bill.
The measures are aimed at freeing up the labour market and reining in France's 10 percent unemployment rate, with youth joblessness nearer to 25 percent.
But critics say the package threatens job security and many feel it will fail to create jobs.
Across France, dozens of high schools and several university campuses were paralysed by protests.
Scuffles broke out in the Place de la Republique in central Paris as students gathered for a march, some setting off smoke bombs.
Two police officers were injured, while three protesters were arrested, police said.
Thousands set off from the vast square in spring sunshine, with banners reading "Insecurity is not a job" and "Flexible, exploited, disposable".
In the western city of Rennes, hundreds of protesters disrupted rail traffic by descending onto the tracks at the main train station, with one waving a sign reading "Let's stop living like slaves".
Youths clashed briefly with police in Marseille in the south.
The protests were staged despite the government presenting a watered-down version of its contested labour market reforms on Monday, responding to demonstrations last week by hundreds of thousands of students and workers against the original proposals.
The main students' union, UNEF, and two of the biggest labour unions, the CGT and the FO, were unimpressed by the changes and repeated their call for the entire draft reform to be withdrawn.
The education ministry said Thursday's protests brought 115 of France's 2,500 public high schools to a standstill, and Paris campuses including the prestigious Sorbonne University were shut as well as universities in the cities of Lyon and Bordeaux.
"We're trying to maximise the youth mobilisation in the street as well as at rallies, before joining ranks with the workers" in more demonstrations planned for the end of this month, UNEF head William Martinet told AFP.
Many young people, including graduates, find themselves working on short-term contracts for several years after their studies, or doing internship after internship while hoping to secure a job.
Their situation contrasts with the job security and perks enjoyed by those on full-time contracts in France.