Police evacuated Paris's Gare de Lyon station after protesters started a fire to try to disrupt a concert by a Congolese singer.
Political opponents of the DR Congo government set fire to parked scooters, motorcycles and bins and blocked firefighters from tackling the blaze.
They accuse singer Fally Ipupa of being too close to the Congolese government.
Police had earlier banned protests against the concert, citing a "tense political context".
A large plume of smoke was visible above the station and smoke was also seen inside the Gare de Lyon metro and suburban rail stations.
Victoria Williams from the UK was in the Gare de Lyon at the time.
"There was big thick smoke. People were surging and setting fire to things," she said. "It just seemed to get very ugly, very quickly. Traffic was gridlocked in every direction, it was pandemonium.
"The protesters were throwing anything they could at the police and fire brigade who were just trying to do their job. They were just setting fire to anything they could and fighting with each other."
Police described efforts to prevent firefighters from reaching the scene as "scandalous behaviour".
Before the concert police had warned of significant calls on social media for protesters to "clash with concertgoers".
One protester told Reuters they had been trying to block people from attending. They say Fally Ipupa is too close to President Felix Tshisekedi, who took power a year ago.
Congolese media said members of the Congolese diaspora had come from other European cities, including London, Brussels and Vienna, to try to disrupt the concert.
Concert is historic for Congolese musicians
By Gaius Kowene, BBC News, Kinshasa
For years parts of the Congolese diaspora have condemned musicians they view as too close to the political elite they blame for destroying the country.
As a punishment they have used direct action to effectively ban musicians from performing in Europe and thereby prevent them making money.
For about 10 years, some members of the diaspora would try to beat up any musician - and anyone who was part of the regime - whenever they visited Europe. It happened to some senior officials in the past few years. Some musicians have had concerts targeted.
Fally Ipupa is the first Congolese artist to perform in Europe since then. It is a historic moment for Congolese music. Many people are saying that his concert will pave the way for others to perform. It is a challenge to members of the diaspora and they do not like it.
Fally Ipupa, who reportedly has a large following in France and has collaborated with several French rappers, was forced to cancel a concert in France in 2011, RTL reported.
Police said 30 people had been arrested and 54 people had been fined for participating in a banned protest.