The 15-year-old goalkeeper will be a part of City’s Under-18 side at the City of Manchester Stadium.
The player’s father, Harald Karius, told Spox: “Manchester City first contacted us after they had attended the German Under-16 side’s game against Macedonia in September 2008.
“We were invited to see the youth and first-team set-ups, the stadium and the area, and they held discussions with his agent.
“We had many offers from England and Germany – 70 percent of Premier League sides wanted Loris.”
He added: “Loris has great talent – if he didn’t, there wouldn’t have been such massive interest in him – but football is all about performances.
“Loris can’t afford to relax. It’s all about hard work.”