A Queens man is suing a Manhattan nightclub for sex discrimination — because he had to pay an entry fee at its “Ladies Night” while women got in for free, according to a new lawsuit.

Patrick McDowell grouses in his suit that he went to Inwood club Republica Lounge on Aug. 10 and had to pay a $20 cover charge — but was told women didn’t have to pay anything, according to his new $50,000 Manhattan Supreme Court lawsuit.

McDowell says the Dyckman Street bar didn’t get permission for the ladies night — a common weekly practice at bars and clubs — from the New York City Commission on Human Rights “to engage in this type of sex discrimination,” as he claims is required, according to the court papers.

“The Defendant in this matter holds “ladies night” events in which females receive preferential treatment and does so without the required permission from the New York City Commission on Human Rights, thus violating the law,” the lawsuit alleges.

“Although the Court may believe that public policy should permit the Defendant to discriminate in favor of female customers, the legislature has set up a specific procedure for public accommodations to make such an argument: They must apply to the New York City Commission on Human Rights for express permission to discriminate on the basis of sex,” it continues.

“In this case, the Defendant has failed to obtain such permission,” the court papers charge.

The Dominican-themed club’s website still has an outdated advertisement for Sept. 14 which says: “Plush Saturdays: Ladies Free All Night.”

In addition to seeking $50,000 in damages, McDowell also wants a judge to stop the club from holding ladies night until the establishment gets proper permission from the Commission.

Republica did not immediately return an email request.