"It's something I love, it's part of my family's culture," said the minister who was born in Spain, where bullfighting is hugely popular, and moved with his family to France when he was a child
"It's a culture that we have to preserve," he told BFM news channel, adding that with France in the middle of economic crisis, it was important to maintain traditions.
"We need these roots, we should not tear them out," he said.
Bullfighting is banned in most of France but is allowed in parts of the south because it is regarded as a cultural tradition, despite complaints from activists that the sport is a form of animal cruelty.
The French constitution bans cruelty to animals, but makes exceptions for bullfights in towns such as Nimes or Bayonne which can prove a long tradition of hosting such events.
The anti-bullfight group CRAC has asked the constitutional council to reexamine whether these exceptions are in keeping with the constitution.
The council said Tuesday after hearing arguments from CRAC and from pro-bullfighting lobbies that it would deliver its verdict on September 21.
"If the corrida (bullfighting) is declared anti-constitutional, then it is the end of the corrida," said CRAC spokeswoman Luce Lapin.
Valls's comments came the same day as residents of the Spanish town of Tordesillas, many on horseback and armed with lances, slaughtered a huge fighting bull in a medieval tradition that sparked angry protests.