Paris police have banned a high-stakes union protest because they fear they cannot ensure security after a children's hospital was damaged and many injured at a recent march.

The decision Wednesday prompted immediate condemnation from leftist politicians and unions. The march Thursday was to be part of protests around France and a one-day strike to express anger at a bill that makes it easier to lay off employees and weakens union powers.

The bill has prompted months of protests that often degenerate into violence by small groups of extremist demonstrators.

Paris authorities asked protest organizers to hold a stationary rally instead of a march through Paris. The CGT union refused and Paris police said in a statement they "had no other choice but to forbid the holding of a protest."