A Frenchman faces prison time for tweets containing an anti-gay death threat and public insults targeting a Paris city official.

Tarek Laboun, a 31 year-old engineer, is accused of posting the tweets targeting Jean-Luc Romero, an openly gay deputy mayor and AIDS activist when Romero was married in 2013. Thursday's trial turns on issues of free speech limits online.

Laboun denies using Twitter or writing the three contentious tweets and has described them as "unacceptable."

Twitter gave French police connection data that linked two Twitter accounts involved in the tweets to the computer of Laboun's father and to his parents' home, where Laboun was then living.

If convicted of a "death threat by reason of a sexual orientation,"Laboun faces up to five years in prison and a 75,000-euro ($83,200) fine.