The Gare de l'Est (East Station) is two train stations: one being part of the Paris Metro line,…read moreconnecting Lines 4, 5, and 7 and the other being the one of seven Paris mainline stations supporting TGV (Train à Grande Vitesse) going to various cities in Europe. My nephew and I had planned a weekend trip to Luxembourg, and this station was the origination of the 2.5 hour high-speed trip, beginning early on a Saturday morning. We came from different places in Paris using Metro, and met up here. The walk from the Metro part of the station to the main central holding area takes a bit of time, with need to closely follow signs pointing to Gare de l'Est.
About 24 minutes before the scheduled departure of our train, the platform number came up on the big board. At that point, we used the QR code from our purchased ticket to pass through the security gate of the platform. Then it was a long outdoor walk parallel to the train until one finds the correct car. We left right on-time.
We came back to the same station from Luxembourg, and it was a simple matter of reversing direction back to the Metro side of the station to get back to our dorm/hotel.