Oscar-winning actress Juliette Binoche and French cinema queen Catherine Deneuve have joined dozens of celebrities in rallying to the defence of the nations deeply unpopular Socialist President Francois Hollande.

In an appeal published in the Journal du Dimanche newspaper, around 60 signatories -- among them writers, musicians, businessmen and sports personalities -- penned a strongly-worded denunciation of the attacks on the French leader, urging an immediate halt to what they termed "Hollande bashing".

The appeal comes as France heads into a crucial 2017 election campaign with the left bitterly divided and the right under pressure from the growing popularity of the far-right.

"From the start, Francois Hollande has been unfairly tried in the court of public opinion by those on the left and the right," said the statement which also listed signatories such as fashion designer Agnes B and singer Benjamin Biolay.

Hollande is the most unpopular French president since World War II, his five-year term in office overshadowed by stubbornly high unemployment and U-turns on key policies and several devastating terror attacks.

He has said he will decide by the end of the year whether to seek re-election.

It listed a string of what were described as Hollande's successes, saying: "All of that is ignored, skewed, erased in place of a daily trial of slurs and despicable lies" and warning it was leading to "a dangerous drift from democracy".