Christian Keller didn't beat around the bush. "That really gets on my nerves," said the managing director of 1. FC Cologne on Thursday after the 1-1 draw at OGC Nice in the Conference League. The impression of the images of the riots overshadowed everything shortly before midnight on the Cote d'Azur, even if the game had taken place anyway and FC had fought for a well-deserved respectable victory.

Keller made it clear that the club would try "with all hardness and determination" to identify those involved in the riots. "I don't know if it was 50, 60 or 70. It was definitely very, very few," he said. "But we'll try everything to get as many people out as possible. And then we exclude them, they won't do anything anymore." The consequences for the club are "not yet foreseeable. I don't want to speculate either. There is certainly a wide range."

Actually, the away game of "Effzeh" on the Cote d'Azur was supposed to be a fan party. Already in the early afternoon almost 10,000 fans of Cologne marched through Nice with carnival music. Nice's mayor Christian Estrosi quickly complained that Cologne fans often left rubbish on the city streets and didn't behave themselves. He wrote on Twitter: "I regret the rude and scandalous behavior of the Cologne fans and the lack of respect for the city, which welcomes them generously and brotherly."

Videos on social networks show, among other things, how Cologne fans damage buildings in the city center.

After the party in the city center, the Cologne supporters went on a fan march to the stadium. They also passed the team hotel, where they enthusiastically cheered coach Steffen Baumgart.

But the mood quickly changed. During the fan march, supporters of Paris Saint Germain are said to have joined the people of Cologne. A fan friendship between the two clubs has existed for decades. At the same time, the fan camps of PSG and OGC are deeply hostile.

Upon arrival at the stadium, the march was reportedly attacked by local fans. Some fans on social media and fan blogs reported attacks with iron bars and knives. Two people are said to have been stabbed. This is reported by RTL.de.

According to information from 1. FC Köln, supporters of OGC Nice initially tried to penetrate the Cologne fan block in the stadium. Then about 100 partly masked Cologne residents stormed across the grandstand in the direction of the Nice fan block. Groups met directly in front of the box, where coach Baumgart was also sitting because he had been banned from the game.

They fired at each other with flares and other thrown objects. Amateur videos also show how men in the colors of Cologne push a man over the parapet of the upper tier. The man fell almost five meters and was seriously injured. He was in mortal danger in the evening, but is said to have stabilized in the meantime.

Many stadium visitors criticized the local authorities for not intervening quickly enough. The stadium - it seemed - was a legal vacuum for a few minutes. Only then could police forces separate the two groups of fans.

The FC officials had kept the pictures of the events away from their professionals. The news that leaked out was distressing enough. And then the team took an oath before the 55-minute delayed kick-off. "We said to the team: Think of the peaceful 7,900 boys and try to hide everything from them as much as possible," said regular assistant coach André Pawlak, who represented his boss Steffen Baumgart, who was locked in the stands.

Striker Steffen Tigges, who gave Cologne the lead at 1-1 in the 19th minute, was motivated by the pictures of the peaceful fan march through the city at noon. "These pictures stay," said the ex-Dortmunder: "They pushed us. Because it's not true that the few chaotic people stand for the club. The fans who created the right atmosphere, they stand for the club."

The goalkeeper Marvin Schwäbe, who was often outstanding as in the weeks, saw it similarly. "On the one hand, what happened there isn't worth talking about because it doesn't belong in football," he said: "On the other hand, you have to clearly distance yourself from something like that and say that these people in the stadium have nothing to do with it search." After all, Schwäbe made it clear: "There were 8,500 fans here, and the majority has a clear head."

Sources: RTL.de, with material from DPA and AFP