Fortuna Düsseldorf's Kerem Demirbay had to apologise to German FA (DFB) referee Bibiana Steinhaus for his comments immediately after she sent him off for a second yellow card late in his side's 2-1 win at FSV Frankfurt last weekend.

“I have apologised to Mrs Steinhaus in person and I am very pleased she accepted my apology,” he said, having scored both goals on Sunday.

Bibiana Steinhaus. Photo: DPA

The DFB are investigating the incident, but Demirbay's club has already suggested an unusual punishment.

“It would be a good thing, if he really wants to prove his true opinion of women, if he goes to a girls' football match — as a referee,” said Fortuna's interim CEO Paul Jaeger.

Demirbay, 22, took to Facebook to publicly apologise to the 36-year-old Steinhaus, who officiated the 2011 women's World Cup final when Japan beat the USA in a penalty shoot-out, and also refereed the 2012 Olympic final in London.

“I am extremely sorry for what I said to Mrs Steinhaus. I should have never said this sentence, because it is not what I think of women,” wrote Demirbay.