Eleven Saint-Etienne fans, two with fractured skulls, were taken to hospital following violent incidents ahead of their club's Europa League defeat at Dnipro Dnipropetrovsk on Thursday.
French media reported members of the 150-strong travelling support were attacked in a bar in Kiev by fans of Dnipropetrovsk, whose team have to play their European games in the Ukrainian capital due to the ongoing unrest in the east of the country.
According to a press release on the Ligue 1 side's official website, the Ukrainian supporters were "armed with knives and air guns."
Those not taken to hospital were able to take in their team's 1-0 defeat in Kiev's Olympic Stadium that meant Christophe Galtier's men finished bottom of Group F.
"Thanks to the intervention of the French embassy, the ASSE supporters will be escorted to Kiev airport in security after the game," the statement read. "Furthermore, the club's board has decided to take those injured home in the plane chartered for the players."
Anton Gerashenko, a spokesman for the Ukraine's Interior Ministry, is quoted by L'Equipe as saying: "Two Frenchmen have head fractures. I think they will remember their visit to Kiev."