Internet giant Google’s Paris headquarters were raided Tuesday by French investigators as part of a probe over tax payments, according to reports. A story in French daily Le Parisien gave details of the search, which is believed to have taken place in the early hours of the morning. Dozens of investigators are believed to have taken part.

It marks the latest escalation in the ongoing battle over the levels of tax paid by internet giants such as Google, who have exploited loopholes in the law to operate profitably in countries while maintaining their tax base elsewhere in countries with lower corporate tax rates, such as Ireland.

France is seeking some $1.79 billion in unpaid taxes from Google, which has come under fire for its liberal use of tax optimisation techniques.

Earlier this year, Google agreed to pay $190 million in back taxes to the UK. Critics of Google’s tax practises blasted the settlement as overly generous in favour of the internet giant.