The 31-year-old has been released by his club Lens, who are currently at the top of Le Championnat in France.
Boro boss Steve McClaren said: "We’re very pleased to have completed the signing of Michaël. He will become a useful squad member as we enter the final phase of the season."
Debeve, who is a former team-mate Franck Queudrue, will have to wait for international clearance before he can be considered for selection.