Rights groups welcomed the decision of the Grenoble appeals court to overturn the three-month suspended sentence given to 55-year-old activist Pierre Mumber.
He had been charged with assisting the migrants and helping them evade a police inspection, charges he always denied.
Mumber told AFP that he was “relieved” by the verdict, which came after the court took into consideration footage shot by an Italian TV crew of the incident in winter 2018 which revealed contradictions in the police account.
Amnesty International also welcomed the ruling, saying all Mumber had done was to offer hot tea and warm clothes to four West African asylum seekers.
“We are delighted that Pierre Mumber has been acquitted today –- this is a victory for common sense, and for a good man who did absolutely nothing wrong,” said Rym Khadhraoui, Research Fellow at Amnesty International.
Several French activists have been prosecuted for helping migrants arriving from Italy after crossing the Mediterranean in often overcrowded boats.
Rights groups accuse the authorities of harassing activists who show solidarity with migrants.