French police said the train station was evacuated and advised people to avoid the area. They didn't elaborate on the cause of the fire.
The UK's Express suggests that the fire was started by a group of protestors voicing their opposition to a music concert by Congolese singer Fally Ipupa. Twitter videos are emerging of streets around the train station engulfed in flames.
Update : Video of the rioters preventing the firefighters from putting out the fires near the Gare de Lyon in #Paris in relation to a concert by a Congolese star
Riot police are moving in to counter the protestors.