The 21-year-old is the sixth young gunner to be on loan this summer after spending last year with VfL Bochum.
In Germany’s second tier, Osei-Tutu played a decisive role in his team’s relegation problems.
Having discovered a midfield house, he scored 3 and scored 3 on an undefeated 11-game streak at the end of the campaign.
Although he was left mourning a pre-season exit for the 2.Bundesliga team when he was the victim of racist abuse opposed to Swiss club St. Gallen.
Osei-Tutu has already made his first outing in the Bluebirds jersey, in a 3-0 friendly win over Newport.
New recruit Kieffer Moore scored a double when Neil Harris’ men began their new crusade after last season’s playoff race.
Osei-Tutu told the club’s website: “I came here because it’s a wonderful club that gives me a wonderful platform.
“I thank the coach for having the conviction to take me to such a glorious club and all I can do is give it back.
“I’ll do it by showing what I can do, the team wins games and pushes for promotion.
“I have clever wisdom about the game on the field, but the right-back is my place. I like to move from one side of the field to the other, attack and defend. I can’t wait to get started.”
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