PARIS (AP) — French financial prosecutors have opened a preliminary investigation into suspected tax fraud by American management consulting firm McKinsey & Company.

The national financial prosecutor’s office said Wednesday the investigation was launched last week for alleged “money-laundering aggravated by tax fraud.”

A report by the French Senate issued last month said McKinsey had not paid corporate profit taxes in the country since at least 2011. The report also questioned the government’s use of private consultants.

The so-called “McKinsey Affair” hasprompted criticism from President Emmanuel Macron’s rivalsand is dogging him at campaign stops ahead of the first round of voting in France’s presidential election vote on Sunday.

The report of the Senate, where opposition conservatives hold a majority, found that state spending on consulting contracts doubled in the past three years despite mixed results and the potential for conflicts of interest.

Dozens of private companies have provided consulting, including giants like Ireland-based multinational Accenture and French group Capgemini.

The report alleged that McKinsey used a system of “tax optimization” through its Delaware-based parent company.

McKinsey issued a statement saying it “respects French tax rules that apply to it” and defending its work in France.

The American company was notably hired to advise the French government on its COVID-19 vaccination campaign and other policies.