About 200,000 people joined a demonstration against the Iranian government in Munich on Saturday, police said, as world leaders gathered nearby for a security conference, AFP reported.
The protesters rallied on Munich's Theresienwiese fairgrounds, denouncing the leadership of Iran's Islamic Republic following the deadly repression of nationwide protests in January.
Some waved flags with a lion and a sun against horizontal green, white and red stripes, the emblem of the monarchy overthrown in 1979.
Human rights groups have reported that thousands of protesters have been killed in Iran.
Rallies calling for international action against Tehran are also planned in Toronto and Los Angeles on Saturday.
The exiled son of the former shah of Iran, Reza Pahlavi, spoke at the Munich Security Conference on Saturday and called on US President Donald Trump to "help" the Iranian people.
Pahlavi, who has lived in exile since his father was overthrown in the 1979 revolution, urged an outside "humanitarian intervention to prevent more innocent lives being killed" in Iran.
The Theresienwiese, which hosts the huge annual Oktoberfest folk gathering, is located less than three kilometres (1.8 miles) from the security conference venue.
Last week, an estimated 10,000 people gathered in Berlin in response to a call from the MEK, an exiled opposition group considered "terrorist" by Tehran.
