FILE - In this Wednesday, June 28, 2017 file photo French Labor Minister Muriel Penicaud leaves the weekly cabinet meeting at the Elysee Palace, in Paris, France. A French investigation into a Las Vegas tech party is putting new pressure on President Emmanuel Macron's labor minister _ and possibly the president himself _ as they pursue difficult reforms to French work rules. (AP Photo/Francois Mori, File)

PARIS - A French investigation into a Las Vegas tech party is putting new pressure on President Emmanuel Macron's labour minister — and possibly the president himself — as they pursue difficult reforms to French work rules.

The Paris prosecutor's office opened a formal judicial inquiry Friday into suspected irregularities in the organization of a costly, high-profile event at the 2016 Consumer Electronics Show that Macron headlined when he was a French government minister.

The inquiry is for "favouritism," but it doesn't name a suspected perpetrator yet, leaving it to investigators to determine later who might be at fault.

The company that organized the "French Tech Night" event, advertising firm Havas, is suspected of having done so without undergoing open tender procedures, among other suspected problems.

It's unclear whether Macron himself was aware and the investigation doesn't target him directly. It is problematic, however, for his labour minister, Muriel Penicaud.

Penicaud directed an agency under the economy ministry — then headed by Macron — that reportedly signed off on the Havas contract.

Penicaud has acknowledged a "procedural error" in the process but says she then launched an internal and external audit and addressed the issue. The agency she headed, Business France, would not comment Friday on the judicial inquiry.

Havas argues that it was not required to compete for the contract because it signed an umbrella agreement with Business France in 2015 for promoting French business that includes such events.

A Havas official showed The Associated Press a copy of the agreement, which included specific references to attracting U.S. investment to France. The document contained no specific requirement of competing in an open tender for organizing individual events.

The cost of the party has also raised eyebrows in France. The Las Vegas event cost 289,000 euros ($238,000), according to the Havas representative, including more than 100,000 euros for renting the conference hall at The Linq hotel and other hotel costs. The Havas official spoke on condition of anonymity because the investigation is ongoing.

Macron used the trip to promote French technology startups, a pillar of his strategy for boosting the French economy.

Another pillar is the labour bill that Penicaud is spearheading this summer, which would make it easier to hire and fire workers and reduce the power of unions. The bill has already sparked anger from unions and is expected to lead to protests by left-wing groups who see Macron as too friendly to the business world.

The Las Vegas inquiry is the latest legal case to cast a cloud over Macron's government just as it is championing a draft law on cleaning up politics.

News from © The Associated Press, 2017