The judge ruled that Strauss-Kahn, also the former International Monetary Fund chief, did not have a claim to diplomatic immunity.
The suit was filed by Nafissatou Diallo, a hotel maid. She claims Strauss-Kahn tried to rape her when she went to clean his Manhattan suite last May. Diallo's claim was one of many relating to Strauss-Kahn's sexual behavior, which doomed his political career.
Criminal charges against Strauss-Kahn were dropped last summer after prosecutors began doubting Diallo's trustworthiness after she lied about her background and actions following the alleged incident.
Strauss-Kahn has denied doing anything violent during his encounter with Diallo.
The Associated Press contributed to this report.