Cédric Herrou, 41, had been prosecuted for bringing mainly Eritreans and Sudanese over the border in 2016 and organising a reception camp on his land near Breil-sur-Roya.
He was initially fined but the punishment was upgraded in 2017 to four months in jail.
Appeal court judges overturned the conviction and sent the case back to Lyon, where he was acquitted on 13 May 2020.
However, the Lyon public prosecutors office launched an appeal against that decision.
“After examining both the admissibility of the appeal and the procedural documents, the court of cassation found that there was no means of admitting the appeal in this case," the judges’ ruling said.
Principle of fraternity
“I am definitely released … solidarity will no longer be a crime,” said Herrou on his Twitter account after the court's verdict.
In July 2018, during one of the court hearings, law chiefs concluded that citizens who offered help of a humanitarian nature to migrants should not be prosecuted even if the migrants are later considered to be illegal.
Herrou’s lawyer, Sabrina Goldman, said Wednesday’s ruling underlined that principle of fraternity.
"Today’s decision puts an end to the relentlessness of the prosecution against Cédric Herrou and allows us to recognise in a definitive way that he has only helped others. It shows that in our republic fraternity cannot be a crime.”
