Conservative MP Aidan Burley was dismissed as parliamentary private secretary to Britain's transport minister after newspapers published pictures of the drunken bash at a posh French ski resort and reported that guests had been toasting the memory of Nazi leaders.
The party's stag or bachelor, Mark Fournier, was subsequently prosecuted for wearing a Nazi uniform and insignia, which is outlawed in France.
A police tribunal in the French Alps town of Albertville upheld the prosecutor's demand for a maximum fine of €1,500 ($2,065, 1,234 pounds).
In addition, it ordered Fournier to pay €1,000 in damages to the Association of Internal Deportees and Families, a civil complainant.
The controversial party took place on December 3, 2011, in a restaurant in upmarket Val Thorens.
Fournier, who was photographed in full SS regalia whilst giving the Nazi salute, initially faced more serious charges including denial of war crimes or crimes against humanity and incitement to racial hatred.
Those were dropped in favour of a sole charge of wearing the uniform of an organisation guilty of crimes against humanity.
Fournier's lawyer, Michel Roubaud, had cited British royal Prince Harry's wearing of a Nazi uniform in 2005 in his client's defence.
"English law does not consider the wearing of a Nazi uniform to be, in itself, a crime. We can see that from the conduct of Prince Harry," Roubaud told AFP earlier, adding that it was just a case of high jinks.
British stag parties, held before a man gets married, are typically jovial, boozy nights out, often with the groom-to-be in embarrassing fancy dress.
Fournier, an Oxford graduate, was also sacked from his job as a result of the controversy.