A court banned France's anti-immigrant National Front party from giving out leaflets attacking plans to build a giant mosque because they used pictures of it without permission.
The ruling was to protect the architects' intellectual property, but also came at a sensitive time after a ban on minarets in neighbouring Switzerland stoked debate about Islam in France, home to Europe's biggest Muslim minority.
The Marseille court ordered the far-right party to destroy all leaflets on which it had reproduced designs for the planned Grand Mosque in the southern city, alongside the slogan "No to the mosque."
It also ordered the National Front to pay €1,500 in costs, according to a copy of the judgment.
The architects' lawyer Armelle Bouty told the court that they had also been attacked on the party's website and the use of their intellectual property on the leaflets was "the last straw."
"In the extremely political and polemical context, that was intolerable," she said.
Despite several local campaigns by the far right, dozens of mosques are scheduled for construction in France. The Grand Mosque in Marseille will have a 25-metre minaret.
President Nicolas Sarkozy warned French believers to refrain from religious "ostentation and provocation," in an opinion article in Le Monde on Tuesday in the wake of the Swiss minaret referendum.
His government last month launched a national debate to garner views on French "identity" that has highlighted immigration fears in France.