The court was told that the star of Dr Zhivago and Lawrence of Arabia became enraged last month during a high-stakes game of roulette when he was in the process of losing €30,000 (£21,400).
He began arguing with the croupier, who was so alarmed by the actor's fury that he summoned the police.
When an officer arrived at the Enghien-les-Bains casino and asked him to leave, Sharif, 71, grew angrier still, began swearing, and then head-butted the policeman. The officer was given two days off work to recover.
Sharif was given a one-month suspended sentence and fined €1,500 for insults and violence directed at a police officer.
He was also ordered to pay €300 damages to the policeman.
At the hearing Sharif claimed that he had no memory of the event.
The incident had been caught on closed circuit television, however.
Despite repeated protestations that his gambling past was far behind him, Sharif was a regular at the Enghien-les-Bains casino, a lakeside building eight miles from Paris.
After his film career waned, Sharif became a world-class bridge player. But he lost much of his earnings betting on cards and horses, and he has readily admitted that it was losses of up to £750,000 a night that compelled him to make some of his worst films.
In a recent interview he claimed that he had renounced gambling.
"Casinos are a place you go to when you arrive in a town where you know nobody," he said, adding that he could no longer afford the luxury of blowing all his money at the card tables.
"The reason that I stopped gambling about 10 years ago is that I'm not sure any more that I can earn all the money that I want ... It's an age where you have to be careful."
Perhaps more revealingly, he admitted in the same interview that he felt he was now old enough to behave how he liked.
"At my age you can die any moment. It's not likely but possible, and therefore I want to do what I feel like doing," he said.
An employee at the expensive Paris hotel where he lives permanently ("It's like home - with lots of servants," according to Sharif) said yesterday that the actor had left to go on holiday and would not be returning for the rest of the month.
No one at the casino would comment on the incident.
