Seven-time Formula One world champion Michael Schumacher has run into trouble over the construction of his SFr35 million ($28 million) villa in Switzerland.
A trade union has found that six French stonemasons at his Lake Geneva property were being paid less than half the Swiss minimum.
The revelation comes just weeks before voters in Switzerland are due to decide whether to open the labour market to workers from the ten new European Union member states.
Opponents of the move claim the lifting of restrictions will lead to a flood of cheaper labour and wage dumping – and the Schumacher affair has given them much-needed ammunition ahead of the September 25 vote.
According to reports, a building contractor working for Schumacher was caught paying the stonemasons SFr13.50 an hour – well below the standard Swiss minimum for such work.
Schumacher's lawyer Bertrand Gros has denied any wrongdoing on the part of his client, saying the German motor-racing ace was not aware of the situation at his villa in canton Vaud.
"The Schumachers were not in the know. It is not the responsibility of our client to ensure that the architects and builders comply with Swiss regulations," said the Geneva-based lawyer.
But this has not spared Schumacher from some unsavoury headlines in the Swiss press.
"Slaving for a pittance," read the front page of the tabloid Blick newspaper, while Le Matin described the news as a "scandal".
Unions, however, have seized on the affair as proof that measures introduced to combat abuses in the labour market are working.
"This is a great showcase because of Schumacher's name," said Ewald Ackermann, spokesman for the Swiss Federation of Trade Unions.
"What people should learn from it is that it does not pay to break local laws and our union members should be encouraged that Swiss wages will not be undercut."
This feeling was echoed by Roger Piccand, who heads the employment office in canton Vaud.
"We don't want the free movement of workers to lead to wage dumping, but this episode highlights that if there are sufficient controls, the advantages of opening our country are bigger than the disadvantages," he said.
The construction company involved in building the villa has already said that it unwittingly underpaid the six French stonemasons and has since increased their wages.
Piccand told swissinfo that a report would now be prepared before deciding what action to take against the firm.
In a separate incident eight German craftsmen – also underpaid by Swiss standards – were found working on two SFr5 million horse stables being built for the Schumacher family.
Like many celebrities, Schumacher benefits from low tax rates in Switzerland where he has lived since 1996.
In May 2005 he was forced to abandon plans to build a luxury villa in the east of the country after environmental groups opposed the project.
But after much courting by other Swiss cantons, Schumacher decided to build a villa on a 13-hectare site in Vaud.
His new lakeside residence will have eight bedrooms, two indoor swimming pools and an underground parking lot for 19 cars.
swissinfo with agencies
The trade union Unia has revealed that six French stonemasons working on Michael Schumacher's villa in canton Vaud are not being paid the Swiss minimum wage.
The incident comes ahead of a nationwide vote on September 25 on whether to extend an existing labour accord with the European Union to its ten new member states.
Opponents claim such a move will open the floodgates to cheaper workers from these mainly eastern European countries.