FILE PHOTO: French Labour Minister Muriel Penicaud attends an interview with Reuters at her office in Paris, France, November 15, 2017. Picture taken November 15, 2017. REUTERS/Gonzalo Fuentes

PARIS (Reuters) - French judges have summoned Labor Minister Muriel Penicaud as part of an investigation into suspected financial misdemeanors by a state body she headed, a source close to the minister said on Tuesday.

Prosecutors launched a probe last year into the way a party promoting France at a consumer electronics fair in Las Vegas in 2016 was organized. President Emmanuel Macron was present at the party in his then-role as economy minister.

Penicaud will be questioned under caution on May 22, the source said, confirming a report by satirical newspaper Le Canard Enchaine. The procedure does not mean she will be put under formal investigation.

Macron has said any minister placed under formal investigation by magistrates must resign, although such investigations do not automatically lead to trial.

There was no open tender to organize the party for Business France, the body Penicaud led at the time. The job was performed by the Havas public relations agency.

Havas has said it had an 18-month contract with the state agency which allowed it to do the job without a public tender.

Penicaud said last year that she was the one who raised the alarm when an audit exposed a potential problem.