Lyon and Besiktas were handed suspended European bans and fined 100,000 euros each on Wednesday after crowd violence scarred their Europa League quarter-final match in France, UEFA said.
The French and Turkish teams were excluded from taking part in the next continental club competition they qualify for but the governing body decided that the suspension will be deferred "for a probationary period of two years".
"Based on the official reports and the current available evidence at the disposal of the UEFA disciplinary bodies, the Control, Ethics and Disciplinary Body (CEDB) has considered that the supporters of both clubs were responsible for the crowd disturbances at the match," said a UEFA statement.
Lyon president Jean-Michel Aulas described the sanction as "fair".
"We will see if we appeal...but we respect the decision of UEFA. We had some responsibility," he said on the club website.
Lyon and Besiktas both blamed opposing fans for instigating much of the trouble at the quarter-final first leg last Thursday, the start of which was delayed by 45 minutes.
However, the Turkish champions were furious on Wednesday, laying the blame with the Lyon police force and threatening legal action against UEFA.
"There is nothing to say about this scandalous decision," Besiktas press spokesman Metin Albayrak told NTV television.
"It shows how biased a decision UEFA has made by putting us on an equal level with Lyon over incidents we were not responsible for," he added.
"Lyon's police should be held entirely responsible for the incidents that broke out."
Hundreds of supporters ran a gauntlet of violence outside the Lyon ground and police used teargas to quell outbreaks of fighting and vandalism.
Lyon supporters then poured onto the pitch as they attempted to protect themselves from firecrackers and other objects raining down from the stands above at Parc OL.
Up to 20,000 Turkish fans, the majority living in France or Germany, were intermingled among the 35,000 supporters of Lyon on top of the 3,000 fans from Istanbul situated in the visitors' section.
Five police officers were injured in the disturbances.
"Everything... is under the responsibility of Lyon. There is no need to punish Besiktas," club spokesman Metin Albayrak told state-run Anadolu news agency before the UEFA ruling on Wednesday.
The second leg of the tie, in which Lyon lead 2-1, takes place in Istanbul on Thursday.
Aulas had expressed fears for the safety of his team in the Turkish city.
But Besiktas chairman Fikret Orman said that Lyon had nothing to be scared of at the team's stadium on the shores of the Bosphorus, distancing the club's fans from responsibility in the violence.
"Here is our home," he said at a club meeting inside the Vodafone Arena stadium.
"Don't be afraid. We are everyone's defender so come here and watch the match in a really nice way."