According to the Action June 11: No Nuclear Power blog, 66,819 people participated in the June 11th action in Japan alone. There were 22 anti-nuclear power events were held in 11 countries outside of Japan. In addition to those countries, there were 32 events in France and more than 200 in Taiwan as far as the organizing group know. They are still counting, but they are expecting the total number would be around 67,000.
Photos from the protest in France
Japan Nuclear Crisis 