Paris ( CNN ) -- Severe weather continued to disrupt travel across Europe Thursday , as heavy snowfall forced a border closure between France and Luxembourg and stranded thousands of airline passengers in Germany 's busiest airport . The relentless snowfall shut down traffic on the A31 , a major highway , which prompted the closing of the border . The severe weather also forced German officials to cancel 239 flights and order a four-hour shutdown of the Frankfurt airport . German 's second largest airport , in Munich , announced the cancellation of 51 flights , most of them resulting from canceled flights at other airports . The border closing and flight cancellations come a day after heavy snow paralyzed travel in the Paris region , where officials suspended air traffic at one of Europe 's busiest airports , closed several highways and shut down the Eiffel Tower . The tourist attraction reopened Thursday as officials downgraded a weather warning for central France from orange to yellow . French police urged motorists to avoid driving unless absolutely necessary to get to work . However , Gérard Gauzet , director of Paris motorways , said Thursday morning that `` traffic should be back to normal by mid-afternoon . '' The Paris Metro is also running smoothly , but weather continues to delay some bus traffic , which was completely shut down by snow on Wednesday . At Charles de Gaulle airport , `` air traffic is almost back to normal , '' according to an airport spokeswoman . `` However , passengers should be prepared for delays and cancellations depending on the airline , '' the spokeswoman said . Snowfall shut down air traffic for several hours in the afternoon Wednesday . The Wednesday traffic jams in the Parisian metro area set a new record . According to the National Center for Highway Information , snarled traffic lined 420 kilometers of roadways around the capital . Shelters opened in the region to take in stranded motorists , and many people reported spending the night in their offices after being unable to get home . Some disruptions were also reported on the region 's railways Wednesday , with the high-speed TGV trains limited to a speed of 230 kph instead of the usual speeds of up to 320 kph , and several trains were delayed . Journalist Celine Martelet of radio station RMC told CNN affiliate BFM-TV on Wednesday she had been blocked on a highway near Paris for three hours . `` There 's an incredible silence , not one noise , '' she said . `` People are leaving their cars and trying to go on foot . I saw one man on skis , who was going to find his wife who was stuck in a traffic jam two kilometers away . He was going to help her get out of her car . '' CNN 's Alanne Orjoux , Saskya Vandoorne and Winnie Andrews contributed to this report .
Thousands of air travelers are stranded at Frankfurt 's airport . French commuters are urged not to travel unless absolutely necessary . The Eiffel Tower falls .