The midfielder has signed a one-year contract with the Danish champions following five years in Ligue 1.
"I have joined a big club, the best club in Scandinavia who play in Europe every year," Braaten told VG.
"I have got some experience. That is one of the things I can offer the club. I am more keen to play football now than I was when I was a young player."
Copenhagen have also completed the loan signing of Georg Margreitter from Wolverhampton Wanderers until the end of the season.