French officials have fined a pub in Brittany €9,000 for “undeclared labour” after a customer returned some empty glasses to the bar.

For customers at the Mamm-Kounifl concert-café in Locmiquélic, carrying drinks trays and used glasses back to the bar was a polite tradition.

But for social security agency URSAFF, it was also an infringement of labour laws because customers were acting like waiters, French local newspaper Le Télégramme reported.

Download the new Independent Premium app Sharing the full story, not just the headlines

“Around half-past midnight, a customer returned a drinks tray. She passed by the bar to go to the toilets. That was when it all kicked off. My husband was pinned against the glass by a man. A woman leapt on me, showing her ID card and that’s when I realised it was a URSSAF check. They told me I had been caught using undeclared labour,” owner Markya Le Floch told Le Télégramme.

“It is a scam. We haven’t committed any wrong doing,” she added.

The authorities initially fined the pub owners €7,900 and briefly placed them in police custody. Customers vouched for the owners and they escaped charges, but URSSAF are still pursuing a social case and are now seeking €9,000 due to non-payment of the original fine. A URSSAF spokesperson told France Bleu they refute the owners’ account of the incident.

“We were shocked by this and we’re certainly not going to pay the fine. This was all a mistake. What happened was completely surreal, but we’ve received a lot of support from our customers, and they also think that this situation is completely ridiculous,” Le Foch told The Independent.

The case will now be examined at a later date at a special court in Britany.