Although Essen is the 7th-or-8th-largest-city in Germany, its biggest club, Rot-Weiss Essen, languish in the Regionalliga West, the fourth tier of German football, and have not played in the top flight since 1977.
The Wikipedia entry on the club goes on the state:
“Due to the general improvement in German football, a trip to the Georg-Melches-Stadion in Essen is not as threatening as it once was. However, it is hardly a relaxing day out and sometimes it can be quite intimidating, although the police shows large presence. It is advised to exercise caution around the ground and not to wear the colours of the foreign club, at least when travelling alone.”
It would be interesting to collate a list of cities, which, although amongst the 10 largest in a country, do not have a football club in the top two tiers of that country’s football leagues.
From England, Leeds and Leicester would be on the list, with Bradford close to making it.
It doesn’t help that in England, the largest urban area is so much larger than the rest, and has 8 clubs in the top two tiers (5 in the top tier). The West Midlands Urban Area has 5 (2 in the top tier), while the Great Manchester Urban Area has 3 (all in the top tier). Although the West Yorkshire Urban Area is the fourth largest, it has no club in the top two tiers.