Bayern Munich on Sunday said it will impose "a heavy fine" on Franck Ribery over an obscenity-laced outburst on social media, after the French striker became embroiled in controversy for eating a gold-coated steak.

The punishment comes after Ribery lashed out at critics in a string of angry posts on Twitter and Instagram on Saturday. It is the latest scandal to engulf the 35-year-old, who is deeply unpopular in his native France but revered by German fans.

"I had a long talk with Franck and I let him know that we would impose a heavy fine on him and he accepted it," the club's sporting director Hasan Salihamidzic told journalists in Qatar, where the club is on a training camp.

"He used words that we, FC Bayern, cannot accept and that Franck does not have the right to use, as a role-model and player of FC Bayern," added Salihamidzic.

On Thursday, Ribery posted a video on social media showing him in a Dubai steak house owned by celebrity Turkish restauranteur Salt Bae and rubbing his hands before tucking into a huge chop coated in gold.

That ostentatious luxury, and the reported cost of the meal, drew ferocious criticism before Ribery -- who earns an estimated eight million euros a year with the German champions -- hit back.

"Let's start with the envious, the angry, surely born because of a broken condom," read the first of the posts on Ribery's Twitter account.

"F**k your mothers, your grandmothers and your whole family tree," he wrote, having taken care to sanitise the French word "n*quez".

Salihamidzic made clear that Ribery did not pay the bill himself because he had been invited to the restaurant.

"Franck has been slandered and insulted," said Salihamidzic. "And not only Franck, but his pregnant wife, his child and his mother, who is currently in hospital for an operation. Franck wanted to defend himself and defend his family. He has the right to do that. I support him in that, but unfortunately he totally lost control."

German media and social media users had called on the reigning Bundesliga champions to punish the striker, who is out of contract at the end of the season after 11 years at the club.

"Bosses must suspend Ribery," urged Germany's best-selling Bild newspaper.

The news portal T-Online went even further, slamming Bayern for not taking firmer action.

"Ribery should not play for Bayern anymore," it said in an editorial. "With this fine, the club falls short of drastic repercussions and that is a fatal signal."

Ribery's outburst comes less than two months after the forward insulted and attacked French TV pundit Patrick Guillou who had criticised his performance following Bayern's 3-2 loss against Dortmund.

Bayern later made Ribery post a video apology on the club website.

Despite being known as one of France's best players, Ribery is little loved at home, partly because of his perceived key role in the French team's infamous training ground strike during their disastrous 2010 World Cup campaign in South Africa.

Ribery's reputation was also damaged by allegations that he had had sex with an underage prostitute although charges in the case were dropped for lack of evidence in 2014.

Ribery announced his retirement from France duty after the 2014 World Cup in Brazil, which he missed due to a back injury.

But run-ins with the media and perceived displays of arrogance have kept Ribery in the headlines, and he has repeatedly been mocked on the French satirical puppet show "Les Guignols" as a dim-witted, out of touch figure.

It's a different story in Germany, where Ribery is known as "King Franck" to grateful Bayern supporters.

Since joining the Bavarian giants in 2007, Ribery has helped the team win the Champions League in 2013 as well as eight Bundesliga titles and five German Cups.

Although he now sees less time on the pitch than in his younger days, Ribery finished 2018 in style scoring four goals in the final three matches of the year.

But Bayern bosses have indicated the current season is very likely to be Ribery's last.