France's highest administrative court dismissed on Tuesday an appeal from the Interior Ministry that aimed to close a mosque in the southwestern town of Pessac for six months.

The local interior ministry's office first closed the mosque for six months on March 14 on the grounds that it promoted radical Islam, incited hatred and justified terrorism. A local administrative court suspended the closure 10 days later, a decision the government appealed.

On Tuesday the Conseil d'Etat rejected the appeal, deeming the closure "a serious and patently illegal violation of the freedom of worship", a court document read.

It is the first time the court has not upheld a government's decision to close a mosque on the basis of a "white memo", a document composed by French intelligence services, bending the latest trend of mosques' being closed by authorities using an array of powers that rights groups and lawyers say infringe on democratic freedoms.

Among the initial accusations against the Pessac mosque was the sharing of pro-Palestinian views on social media, which the government said were anti-Semitic, or messages of support to personalities and organizations "promoting a radical Islam".

But the mosque's lawyer, Sefen Guez Guez, said nothing in the case established a link between the mosque's activities and inciting terrorism. He said the Pessac mosque was an open and peaceful place of worship, whose members mobilized to defend successfully by gathering in front of the courts during both hearings.

"That decision sets a legal precedent which will slow down the successive mosque closures we've seen these past few months, Guez Guez told Reuters. "We hope it is a cooling down sign."

The Interior Ministry said it duly noted the decision and declined to comment further, a spokesperson told Reuters.