Thousands of firefighters across France have travelled to Paris to join a protest calling for better working conditions and a rise in risk pay.
Videos of the protest posted to social media on Tuesday showed firefighters responding to tear gas being fired at them by police, and scuffles with officers using their batons.
Firecrackers could also be heard being deployed, while orange flares doused parts of the protest route in an orange glow.
According to the Paris police department, officers intervened after several hundred protesters broke away from the main procession, while others attempted to break down safety barriers keeping them on course.
"Respect for the rules applies to everyone, whatever the nature of the event," the force said alongside a video of protesters who appear to ram a barrier.
The demonstration, which comes after similar action in October, was organised to call for a rise in firefighters' risk pay - something that hasn't been increased since 1990 - from 19% of their salary to 25%.
They are also calling for better recognition of the riskiness of their profession, and a response to the number of attacks against personnel - which they say are on the rise.
Tuesday's demonstration saw firefighters gathering at Place de la République in central Paris, before marching toward Place de la Nation.
In the evening, unions said they were now calling off their action after France's interior ministry made concessions, including a raise to firefighters' risk pay.