In a Facebook message, Wu told The Observers he had brought the banner with him from Taiwan and that he has received support from people in France and Taiwan.(The text below has been edited for clarity.)

I showed this banner because I knew Xi Jinping would pass by. I wanted to show Xi Jinping and the world the determination of the Taiwanese people to seek and protect our independence, freedom and democracy. When the police officer took away my banner, I shouted my slogans ("Taiwan independence" and "refuse one country, two systems") really loudly.



They put me against the wall and searched me and my bag. After they finished their search, they put me in their van for more than an hour. Two officers were by my side. At first, they didn't want me to speak, but after a while, we started chatting. And that's why I know that there was an order from a "high level" to prevent any type of protest.



They released me after keeping me in their van for more than an hour. They returned my passport and my student card, but they took away my banner! They said they were sorry but they couldn't return my banner. "How can this be a threat?" I was just standing by the road and wanted to wave my banner. How can this be a threat?



A lot of the comments [on the Facebook video] are crazy, like "Why didn't the police put a bullet in your head? Why didn't they punch and kill you? Why didn't you set yourself on fire?" Most of these comments are left by fake accounts that are organised really well by the Chinese military. They will target and attack certain posts or certain people, it happens quite often in Taiwan. I'm already used to it, but my parents are very worried for my security.



But some really crazy comments are from Taiwanese people. They are mostly very conservative and still have their China dream.



It's not only people from Taiwan who are supporting me. Some French people are also supporting me by sending me a personal message, like my friends here or French people who live in Taiwan.

"There is no legal basis"

Michel Tubiana, honorary chairman of the Paris-based Human Rights League, said it is common for law enforcement officials to confiscate protesters' signs under the pretext that they are “dangerous” or could cause "public disturbances," but there is almost never any "legal basis".



The French national police force did not respond to a request for comment.

During his official visit, Xi sought to promote his new economic project, known as the New Silk Road, and signed more than a dozen contracts with France, including a 300-plane order with Airbus and a deal with energy company EDF to build an offshore wind farm in China.

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China has long considered Taiwan, which is self-ruled and recognised by only a handful of countries, as part of its territory. In January, Xi said he was prepared to use force to reunify Taiwan with the mainland and called for a "one country, two systems" model, similar to that of Hong Kong, that would allow the island state to continue govern on its own. President Tsai Ing-wen of Taiwan rejected the proposal.



This article was written by Chloé Lauvergnier (@clauvergnier).