The defender, who has been free since the end of his contract with Bayern Munich at the end of last season, signed a two-year contract that runs until the summer of 2023.
Boateng’s lack of association with any team made him able to move to Lyon after the end of the transfer window on August 31.
The 32-year-old played for Bayern Munich for 10 years, winning 9 league titles and two Champions League titles with them.
Lyon is ninth in the French league table after 4 rounds.
The Strasbourg match on September 12 may witness the German defender’s first participation in a Lyon shirt.