PARIS (AP) — Thousands of protesters marched Tuesday in Paris as France's Senate approved a hotly debated government bill reforming labor laws. The march was mostly peaceful but police used tear gas to counter some demonstrators throwing projectiles.

The march from the city's Bastille plaza to its eastern Italy plaza came under close police watch and minor scuffles occurred when some protesters tried to damage bus shelters. The Force Ouvriere trade union estimated the crowd at 55,000 people while police said 15,000 took part.

Marches also took place in other major French cities.

The Socialist government wants the reforms to make it easier to lay off employees, allow temporary extensions of the work week and give company deals priority over industry-wide deals. Some unions argue it would weaken workers' rights.

During two weeks of debate, the Senate, led by a conservative majority, substantially changed the bill to make it more pro-business. On Tuesday, senators approved it 185-156.

Yet the labor reforms must be debated again in July at France's lower house of parliament, the National Assembly, led by a Socialist majority.

The head of the left-wing CGT union, Philippe Martinez, told reporters "public opinion is still largely against this text."

"We want dialogue, not an absence of dialogue, so that's the government's problem," Martinez said Tuesday.

The bill has led to a dozen protests in recent months, often tinged by violence.

The Eiffel Tower was closed Tuesday due to a strike by some employees. The company running the monument says there were not enough workers to assure security and public amenities.

Air France, meanwhile, warned customers of some delays and last-minute cancellations due to a strike by some air controllers.