Sacré bleu!

As many as 4 million bottles of cheap Spanish wine have been sneakily disguised as more superior French rosé, a sobering new report has found.

Up to 3.4 million liters of plonk was sold in bulk — and passed off as the real deal — with fake labels indicating the wine was “produced in France” and “bottled in France,” according to BBC News.

Shady producers also hid the true origin of boxed wine underneath packaging and beneath the handle.

The bogus blush was sussed out by investigators with France’s Directorate-General for Competition, Consumer Affairs and Fraud Control between 2016 and 2018.

The anti-fraud agency found four producers at fault — and prompted French newspaper Le Parisien to put revelers on high alert.

“Rosé-lovers beware,” the paper warned Monday. “You’re in danger of a nasty surprise at happy hour.”

The winemakers could be charged criminally and face penalties of up to two years in prison and a fine of 300,000 euros ($352,000).

The grape deception comes as local French wine producers duke it out with their Spanish counterparts who import cheaper varieties of vino.

As many as 66.5 million bottles of wine had been misrepresented as Côtes du Rhône between 2013 and 2016, the same anti-fraud agency reported earlier this year. The dupes affected winos in France and the UK.