The firm said the accident happened on November 3.
A FlixBus traveling from Paris to London turned over in wet weather in northern France, injuring 33 people, four of them seriously.
A spokesperson for FlixBus, a German transport company that operates intercity bus journeys across Europe and the U.S., told Euronews that one of its long-distance buses was involved in an accident at 12 p.m CET near Ablaincourt-Pressoir, near Amien.
"According to the latest findings, there were 32 passengers and one bus driver on board. Injured passengers were taken to local hospitals; those not requiring medical attention are being taken care of by local authorities," the spokesperson said.
"FlixBus is in close contact with the relevant authorities in order to determine the exact cause of the accident and to ensure all passengers receive appropriate support. An emergency phone number is available for the passengers and their relatives," it said.
Nationals of France, the U.S., Spain, Austrlia, the Netherlands, UK and Russia were travelling on the vehicle and have been taken to various hospitals near the site of the accident, a local newspaper reported.