A head-on collision between two trams injured 68 passengers in France.

The crash occurred on January 11 afternoon, when a stationary tram at the underground stop was struck by another tram that began moving backwards at Strasbourg's main railway station.

The reversing tram reportedly rolled down a slope and smashed into the stationary one, injuring dozens of passengers.

Footage shows alarms blaring as terrified commuters were heard screaming inside the trams. Smoke wafted from the damaged cars and slowly filled the station.

Authorities said dozens of passengers were aboard both trams at the time of the collision. Emergency services reported that 68 people were injured, while around 100 others were unharmed.

One passenger, Romaric Koumba, said: 'As we were setting off again towards the station, we realised that there was already another tram that had returned to the station. This tram was at a standstill. When the tram collided with the other one, the doors flew off.'

Another onlooker, Johan Kirschenbaum, recalled hearing a loud 'big bang' as the trams collided.

Tram service was temporarily suspended at Strasbourg's main train station, one of the busiest in France outside of Paris, following the crash.

Strasbourg transport company (CTS) director Emmanuel Auneau said both tram drivers were uninjured but 'very shocked' by the accident.

Officials have launched an investigation to determine the cause of the crash.