Local officials say the bride was shot dead on her wedding night in a village near the city of Avignon in southeastern France after a masked gunman set off a fire.
One attacker was killed in an obvious fire exchange, and Groom and the 13-year-old were seriously injured during an incident in the village of Gould.
Manhunt, which involves dozens of police officers and helicopters, is ongoing for an unknown number of suspects who were able to escape.
French media reports that violence may be linked to drug-related scoresetting.
Authorities have launched an investigation into the murder and attempted murder.
On Sunday at 04:30 (02:30 GMT), the 27-year-old bride and the 25-year-old bride and groom had left the wedding party in the village hall when the unidentified assailant fired, AFP news agency reports.
Initial reports suggested that one of the attackers had been hit by the couple’s car, but Avignon prosecutor Florence Gartier cried out that the “exchange” had been hit.
The surviving attacker, arriving by car, fled on foot after the shooting, prosecutors said.
A total of 28 people were in the hall at the time of the attack, police said. One woman was also mildly injured in the incident.
The hall was booked in March “for weddings by people who do not live in the commune,” local Mayor Didier Perelo said.
“I’m furious,” he added. “We’re close to town. I don’t name them. Unfortunately, we’ve seen this kind of thing before.”
Guillaume Molinas, the 50-year-old restaurant owner, said he feared the fatal attack would give a “bad name” to the village of about 1,000 residents.
“The last major incident in the village was 125 years ago,” he was quoted as saying by the AFP without giving details.