Hinkel has been without a club since his contract with Celtic expired at the end of last season. The 29-year-old has signed a one-year contract with Freiburg.
“I am very happy that I have signed for Freiburg and the waiting is over,” he told the club’s website.
“I want to be fully involved in the team from day one and it is great that I have joined such a well-run club.”
