Whether the "Upper Deck" or "Lower Deck" of a double-decker TGV Duplex is better depends on your travel priorities. The Upper Deck is generally preferred by tourists because it offers far superior panoramic views of the French countryside and is often quieter, as there is no foot traffic passing through the carriage to reach other cars (passengers only enter from the stairs). However, the Lower Deck is better for travelers with heavy luggage, families with strollers, or anyone with limited mobility, as you don't have to navigate the narrow, steep spiral staircase with your bags. The lower deck also tends to feel more stable during high-speed turns, whereas the upper deck can have a very slight "swaying" sensation. In 2026, most TGV Lyria and InOui trains allow you to choose your deck preference during the booking process for no extra charge; if you want the "classic" high-speed experience with a view of the vineyards at 320 km/h, always aim for a window seat on the upper deck.