11 held after fans clash in Paris
Eleven people have been arrested after rival football fans clashed in the heart of Paris.
About 40 fans of each side fought in the French capital's historic centre in a "short but violent altercation" outside the Odeon metro station that left several people with minor injuries, PSG's director of security Jean-Philippe d'Halliville said.
He added that fans of another German club, Kickers Offenbach, reinforced the Leverkusen contingent.
Mr d'Halliville said the groups charged at each other twice, and added that the clash was "probably pre-arranged", with the presence of fans from another club lending credence to that. He added that nine of those arrested were from the German contingent and two were PSG fans.
PSG have tried hard to eradicate a long-standing hooligan problem. Two PSG supporters died in separate incidents outside the Parc des Princes stadium in 2006 and 2010.
PSG's group match at Anderlecht earlier this season was considered high-risk and around 150 known PSG hooligans were rounded up by police before that game in Brussels.
In the same area of Paris in December 2008, fans of PSG and Dutch side FC Twente fought a pitched battle in a side street close to the landmark St Michel fountain before a Uefa Cup match, as Christmas shoppers scattered for cover.
Hundreds continued the violence outside the stadium later that night.
There were also violent clashes between PSG and Dinamo Zagreb fans in the Bastille area of Paris the night before PSG's home game last season, despite the French Interior Ministry issuing a decree banning Zagreb fans from the match. PSG had not provided club travel for its supporters to Zagreb two weeks prior to that after consulting Uefa.
Last season's league title celebrations turned into a fiasco as fights between fans and riot police left more than 30 people injured and led to several arrests.
PSG had serious problems with hooliganism from 1985 to 2010, as rival factions at the Parc des Princes - the Kop Boulogne and Tribune Auteuil - were violently opposed. The club took measures to tackle the issue.