PARIS (AP) — Paris police fired tear gas at demonstrators Thursday as the Eiffel Tower shut down, France’s high-speed trains came to a standstill and hundreds of thousands marched nationwide in a strike over the government’s plan to overhaul the retirement system. At least 90 people were arrested in Paris by evening as the protests wound down. Police said 65,000 people took to the streets of the French capital, and over 800,000 nationwide in often-tense demonstrations aimed at forcing President Emmanuel Macron to abandon pension reform. The open-ended walkout by the country’s unions represents the biggest challenge to Macron since the yellow vest movement against economic inequality erupted a year ago.