LISBON, Portugal (AP) — A Portuguese politician who campaigned against real estate speculation has quit after it emerged he bought a downtown Lisbon building for 347,000 euros ($405,000) and renovated it for sale with a list price of 5.7 million euros ($6.7 million).

Ricardo Robles resigned his seat on Lisbon City Council on Monday, saying controversy over the deal had become a political problem and made it hard for him to do his job.

Robles said he bought the building, which includes 11 apartments, in 2014 with his sister. A luxury real estate company started advertising it last February.

Robles belongs to the Left Bloc, a radical left-wing party and an important backer in parliament of Portugal's center-left Socialist government.

The party had defended Robles' conduct, saying he did nothing wrong.