"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.
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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.