PARIS — The French authorities are moving aggressively to rein in speech supporting terrorism, employing a new law to mete out tough prison sentences in a crackdown that is stoking a free-speech debate after last week’s attacks in Paris.

Those swept up under the new law include a 28-year-old man of French-Tunisian background who was sentenced to six months in prison after he was found guilty of shouting support for the attackers as he passed a police station in Bourgoin-Jallieu on Sunday. A 34-year-old man who hit a car while drunk on Saturday, injured the other driver and subsequently praised the acts of the gunmen when the police detained him was sentenced Monday to four years in prison.

All told, up to 100 people are under investigation for making or posting comments that support or try to justify terrorism, according to Cédric Cabut, a prosecutor in Bourgoin-Jallieu, in the east of France. The French news media have reported about cases in Paris, Toulouse, Nice, Strasbourg, Orléans and elsewhere in France.

The arrests have raised questions about a double standard for free speech here, with one set of rules for the cartoonists who freely skewered religions of all kinds, even when Muslims, Catholics and others objected, and yet were defended for their right to do so, and another set for the statements by Muslim supporters of the gunmen, which have led to their prosecution.