Dominique Strauss-Kahn, the managing director of the International Monetary Fund, was ordered on Monday to be held without bail over allegations that he had sexually assaulted a housekeeper in a lavish suite at a Midtown hotel.

The decision to deny bail was a surprising and striking defeat for Mr. Strauss-Kahn, whom many saw as a leading contender to become France’s next president. He was taken to Rikers Island, where he will be held in protective custody in a single-person cell.

Prosecutors had asked the Criminal Court judge, Melissa C. Jackson, to remand Mr. Strauss-Kahn, 62, to custody, contending that he was a flight risk. They also indicated that he may have been previously involved in a similar episode.

“Some of this information includes reports he has in fact engaged in conduct similar to the conduct alleged in this complaint on at least one other occasion,” said Artie McConnell, an assistant district attorney, adding that the other occasion, which occurred outside the United States, was still being investigated.