"We will not start chasing our players and ask them whether their wives are barbers," a Union Berlin spokesperson said.
The German Hairdresser Association has asked the German Football Association (DFB) why footballers have taken to the pitch with fresh haircuts.
RB Leipzig missed the chance to go top of the Bundesliga as they were held to a 0-0 draw at home by Cologne on Saturday.
VfL Wolfsburg twice fought back from a goal down to earn a 2-2 draw against FC Cologne at the Rhein Energie stadium on Saturday.
Borussia Dortmund suffered a shock 2-1 loss to visitors Cologne on Saturday to drop four points off the pace in the Bundesliga title race.
Union Berlin's Max Kruse scored a second-half winner as they snatched a 2-1 victory at Cologne on Sunday to stretch their club-record unbeaten run.
With no public carnival celebrations in the city this year, a clown unveiled Cologne's kit with the slogan: "We are celebrating alone, together."
Champions Bayern Munich won 2-1 at Cologne on Saturday with goals from Thomas Muller and Serge Gnabry returning them to the Bundesliga summit.
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