"Yes, I want to be the next mayor of Barcelona. The decision is up to the Barcelonans," he said in a speech at the Center of Contemporary Culture in the main city of Catalonia.
Valls, who represents the department of Essonne in the French parliament, promised to stand down next week. He added he would run as an independent and proposed to create a civic platform.
The 56-year-old complained about a rising burden of tourism and lack of security in the streets of Barcelona. Better management and putting the city first are a way forward, he said.