Around 20,000 fans of the Bundesliga side are in the capital to celebrate their first European game in 20 years, even though the away allocation for the game at the Emirates is just 2,900.
A spokesperson for the Met Police confirmed that Oxford Street in the West End was effectively closed to traffic as Koln fans marched down the iconic road, but added that there had been no major disturbances so far.
"At around 3pm BST on Thursday, 14 September a large group of football fans gathered in Oxford Street," said a Met statement. "The group was at the location for about 30 minutes whilst they boarded public transport to travel to a football match this evening.
"They did throw bottles and let off flares, but there was no significant disorder, police were on scene and there have been no arrests. The group has now left the area."
Watch a video of Koln fans on the march below: