An investigation by France's anti-fraud watchdog has found millions of bottles-worth of Spanish wine either being falsely passed off as French or poorly labelled to make French consumers think it is homegrown, say officials.

Fraud police found evidence that some pichets – or pitchers – sold in France’s restaurants did not always contain the wine listed on the menu, as well as bag-in-box wines and bottles sold via retailers that appeared to have obscured the origin of their contents.

Most retailers and restaurants audited across 2016 and 2017 complied fully with labelling rules, said France’s anti-fraud body, DGCCRF, keen to put some perspective on the problem.

But, it said there were several instances of Spanish wines being sold as French, with the amount of wine involved in individual cases ranging from 2,000 hectolitres to 34,500hl – up to 4.6 million bottles-worth.

It is the latest in a series of fraud investigations targeting the wine industry and supply chain in France, suggesting that French officials have taken a more proactive stance towards the sector.

The DGCCRF said that it examined imported wine as a whole, although Spanish wine imports became a particular focus.

It said that it audited 179 outlets in 2016 and 564 in 2017, finding that 22% and 15% of those surveyed in 2016 and 2017 respectively had wines falling foul of labelling rules.

Common issues included Spanish wine ‘sold in bulk as French wine or even usurping a French IGP name’, the watchdog said.

If found guilty of such deception, those involved faced fines of up to 10% of annual turnover, or 300,000 euros – whichever is greater – and up to two years in prison.

No specific companies or retailers were named.

In other cases, fraud officers found examples of imported wines sold as bag-in-box that only mentioned the true origin of the wine on the underside of the box. Others used terms such as ‘bottled in France’ or images of châteaux on labels.

One shop was forced to remove 16,700 bottles of Spanish wine from shelves, the DGCCRF said.

It added that there was also evidence of problems in some French restaurants and cafes.

‘One restaurant owner sold a pichet – or pitcher – of IGP OC wine when the wine was actually Spanish,’ the watchdog said, following several inspections.

French media, which has widely reported the DGCCRF findings, has said that officers found a particular problem with rosé wine.

Results of the latest investigation could provoke a sense of vindication among wine unions in Languedoc-Roussillon, which have complained in recent years about the flow of cheap Spanish wine into France; also claiming that some of it was not being labelled properly.

There has been violence, too, such as the hijacking of tankers crossing the Spanish border, although wine unions themselves have condemned such actions.