Paris prosecutors last month reopened an investigation into claims that Darmanin, 35, pressured a woman into sex in return for promising to help clear her name in a legal dispute.
The case comes in the midst of a global outpouring of accounts of sexual harassment and rape unleashed by the Harvey Weinstein affair.
Sophie Spatz, a 46-year-old former call girl, made a first complaint against Darmanin in mid-2017 but the investigation was closed soon after when she failed to attend questioning by the police.
In mid-January she renewed her complaint, triggering a new preliminary inquiry.
Darmanin’s lawyers have accused her of a “crude attempt to harm” the minister’s reputation and said he was suing her for slander.
Government officials have rallied in support of Darmanin, fending off calls for his resignation.