Genshin Impact Joyeux Vouchers are the new collectible for this year's Secret Summer Paradise event, and like previous years, grabbing them will allow you to get a free outfit for h25 one of your characters. This time around, it's Kaeya's Sailwind Shadow outfit, which apparently features in the event questline. If you want his new threads, you'll have to explore the Veluriyam Mirage area in Sumeru and collect these tickets.
Since there are some parts of the new region that haven't been unlocked yet, not all vouchers are currently available, but they will open up as the u31 event questline progresses. That said, here's where to find Joyeux Vouchers and the different ways that you can get them.
Joyeux Voucher locations
You can get Joyeux Vouchers by collecting the multicoloured balloons that are scattered around the new Veluriyam Mirage area—simply walk through one and you'll get four vouchers. When you get close, they'll show H25 up on your minimap with a little balloon icon, but the best way to see all those currently available is on miHoYo's official interactive map. You can grab Joyeux Vouchers from the first two regions that unlocked with the initial quest, but there are still two other areas to come. Since there are two more quests yet to arrive as part of the Secret Summer Paradise event, it's safe to say that those quests will unlock them.
You can also get Joyeux Vouchers by opening chests across the region, though each chest only gives you one voucher. You can unlock these by defeating monsters, solving puzzles, and completing challenges in the Choo-Choo Cart. There are also chests encased in water where you need to examine nearby objects to uncover a Hydro Eidolon droplet that'll unseal them for you.
Since chests reward so few vouchers, you're probably better waiting for the new areas to unlock. You only need 150 Joyeux Vouchers to get Kaeya's Sailwind Shadow outfit from the event page, but if you want to speed up the process, you can grab the Flowing Joyspar gadget once you collect 90, revealing all nearby vouchers you can get.