Herrou was unrepentant after the verdict, saying migrants from poor countries still needed his help and that he would continue to give it.
“We will continue to act and neither the threats of officials or one or two politicians will stop us,” he told a small crowd of supporters outside the court building in Nice.
“It will only be a victory when we do not have to do this anymore and I can go back to my normal life and my work,” he added.
Herrou was found not guilty of putting up around 50 migrants from Eritrea in an abandoned holiday camp.
At his trial last month, he said he was compelled to help migrants “because it has to be done… Families are suffering.”
His lawyer Zia Oloumi said the verdict was “fair,” adding: “This shows that the court understood that he was acting for humanitarian reasons.”
Herrou also defended his decision to put up five minors — a Sudanese youth and four Eritreans — at his home, saying it was up to local officials “to face up to their responsibilities.”
He is one of several people to appear in court in southern France recently charged with illegally assisting migrants who have traveled up through Europe after crossing the Mediterranean in rickety boats.
Their cases have pitched the spirit of solidarity against the letter of the law at a time when border controls and migration have become hot issues in the run-up to this year’s presidential and legislative elections in France.
On January 7, a court acquitted researcher Pierre-Alain Mannoni, who had faced a six-month suspended jail sentence for aiding Eritrean migrants who entered France from Italy.
France has accepted relatively few migrants compared with the 900,000 taken in by Germany in 2015, but many travel though the country, often on their way to attempt to reach Britain or other countries in northern Europe.