The Eiffel Tower closed down and France's high-speed trainsstood still Thursday as labor unions launched nationwide strikes.The unions are protesting the government's plan to reform the retirement system.Officials in Paris set up barriers around the home of France's presidentand deployed 6,000 police officers as activists gathered for a march through the city.Many of the protesters wore yellow vests.The strikes are the biggest test to the presidentsince the yellow vest movement for economic justice was launched a year ago.Organizers hope a mass show of anger toward his reform planwill force the government to make concessions.To Macron, the reforms are central to his effortto make France more competitive internationally.His government argues that the country's 42 retirement systemsneed to be simpler and more effective.All French retirees receive a government pension,but there are differences across the retirement systems.People working for private businesses are part of the general pension system.They make up about seven in 10 workers.But experts and professionals in many fields have a special pension plan.Some people, like railroad workers and flight crews,are permitted to take early retirement.Others, like doctors and lawyers, pay less tax.Macron wants to replace the retirement system with a unified plan,so that all workers have the same pension rights.While some private sector workers welcome Macron's reform,others support the strikers.Public sector workers fear Macron's reformwill force them to work longer than those in the private sector.They also fear it will reduce the size of their pensions.They see the strike as an effort to save France's protections for workers.Joseph Kakou works as an overnight security guard in western Paris.He walked an hour to get home to the eastern side of the city on Thursday morning.He told The Associated Press,"It doesn't please us to walk.It doesn't please us to have to strike.But we are obliged to because we can't work until 90 years old."Many foreigners canceled plans to travelto one of the world's most-visited countries because of the strike.Unprepared tourists arrived at empty train stations Thursday,with about nine out of 10 high-speed trains canceled.Signs at Paris' Orly Airport showed "canceled" notices,as about 20 percent of flights were grounded.Some travelers showed support for the striking workers.Others objected, saying they were caught in the middle of someone else's fight.Vladimir Madeira of Chile had traveled to Paris for a vacation.He said the strike has been "a nightmare."Madeira said he had not heard about the protest until he arrived in Paris.He had planned to travel directly from France to Switzerland on Thursday,but travel cancellations changed his plans.Near the closed Eiffel Tower, tourists from Thailand, Canada and Spain expressed similar concerns.Metro stations across Paris were closed, causing traffic delaysand leading many people to share bicycles or use electric scooters in near-freezing temperatures.Many workers in and around Paris worked from home or spent the day with their children.Almost 80 percent of teachers in the French capital were on strike.In preparation for possible violence and damage on the route of the Paris march,police ordered all restaurants and other businesses along the way to close.Police closely inspected more than 3,000 people arriving for the protestand detained 18 people even before it started.Embassies warned visitors to avoid the protest area.Parisians are not the only ones striking.Thousands of union activists marched through French citiesfrom Marseille on the Mediterranean to Lille in the north.It is unknown how long the strike will last.Transport Minister Elisabeth Borne saidshe expects the travel difficulties to continue through Friday.Labor unions say the protest is an open-ended movement.They hope the strike continues for at least a week,in hopes of forcing the government to change its plans.