The advertising standards authority in Brussels took action after receiving 200 complaints saying it was "vulgar" and incited sexual harassment.
But the firm and the advert's design agency Duval Guillaume said the TV and print commercials were meant to amuse and warn young people not to accept the first job on offer.
The advert features British actor Frank Scantori stripping naked and clambering onto the desk. He then offers the young woman job-seeker a contract, which he uses to cover his groin.
"There's a real war for talent going on, employers go further and further to hire new talent," Jens Mortier, creative director of Duval Guillaume, told BBC News Online.
"But Adecco says live a little before you sign up and get to know the market and yourself first.
"Do not get seduced by all the things employers are offering - the campaign is a parody of this situation."
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Mr Scantori - who weighs in at 18.5 st at a height of 5ft7in - told BBC News Online he thought the fuss was "ridiculous".
"To say it incites sexual harrassment is ridiculous as I am the one who is being seen as a sexual object," he said.
"I wonder if it would have caused the same fuss if I had been some sort of Adonis figure?"
Adecco is one of the world's largest recruitment agencies. Its chief executive in the UK, Richard Martin, explained the reasoning behind the commercial.
"Good advertising is all about impact and these ads use dramatic and exaggerated images to convey a serious message," he said.
But Jean Claude Dastot of the advertising standards authority in Brussels said those who had complained about the ad had expressed shock at its indecency.
Mr Dastot added that nudity was not generally frowned upon in advertising in Belgium but that it "depended on the product".
As well as the ban, the advert has triggered a court case. Adecco successfully sued RTBF - Belgium's public service network - when it refused to show the ad.
But not everyone finds Mr Scantori's strip act offensive. In Holland, the public love it and have nominated it for the best advert of the year award.
"The mixed reaction of the Dutch and the Belgians just goes to show that sometimes you simply can't export ad campaigns across national and cultural borders and hope they will get the same reaction," said Mr Martin.
"But would we run the campaign in the UK? No - we would do something of our own," he added.