If you were slapped with a red-light camera ticket in the city since 2013, take note.

A Brooklyn man is suing the city over the cameras, using a legal loophole to claim that the Department of Transportation has been illegally issuing tickets with their help.

The plaintiff, Monroe Street, filed his Manhattan Supreme Court lawsuit late Thursday after he was issued a $50 fine for allegedly blowing a red light in Brooklyn on March 7.

Street claims that his ticket’s accompanying ”Technician’s Certificate” — which is designed to ensure that a worker double-checked the red-light camera photo to verify the violation — wasn’t notarized, which is illegal.

Street says he tried to fight back against the ticket online but wasn’t able to face or question his accuser, so he lost his case and was forced to pony up the $50 — violating his right to due process, according to the court papers.

Street’s suit wants all red-light camera tickets issued to anyone since Aug. 26, 2013, to be vacated.

“The essential argument is that these ‘technician’s certifications’ are not notarized, and in order for them to be valid, they must be notarized,” said Street’s lawyer, Israel Klein. “The way these tickets are handled is that no technician comes forth to testify.”

Klein said drivers must either go online or “you are there [in court] in front of an administrative law judge” — and either way, “the only meaningful evidence against you is this technician certification, which is not notarized.”

Officials with the city Law Department, DOT and Department of Finance are listed as defendants.

The Law Department said in a statement, “NYC’s red light camera program is fully consistent with the law and saves lives. A number of the claims in this suit are based on an incorrect interpretation of the law, and we will respond accordingly in the litigation.”

Street and another plaintiff in June brought a similar case against the city for its speed cameras. That case is still pending.