Romanians have expressed outrage at a cartoon in the French satirical newspaper Charlie Hebdo likening their newly crowned tennis champion to a Gypsy scrap metal collector.

The caricature in Thursday's edition of the weekly showed Simona Halep holding up her French Open trophy and shouting "Old iron! Old iron!" It sparked immediate uproar on social media.

The French ambassador to Romania, Michele Ramis, on Friday defended "freedom of expression and a free press," adding that the cartoon "doesn't at all represent French public opinion.

Halep, who received a hero's welcome on her return to Romania after the weekend victory, said she wasn't "in a position to comment."

Brussels-based Romanian journalist Dan Alexe, however, said he believed the joke was directed at "ignorant French who think all Romanians are metal thieves."