Fraises (or "strawberries" in French) is a form of micro-currency currently only found in Transformice and Dead Maze, which is an inter-game micro currency that transfers between games that use them, not requiring a special exclusive micro-currency for each Atelier 801 game. They are introduced to Atelier 801 games when they become popular enough to warrant fraise-only content for.
Fraises cost real money, but 1 fraise could be obtained in some adventures. Although you have to pay for them, they can be used to buy items from the shop at a lower price than the normal cheese.
Another way to get fraises is through watching fraise videos, which are 15–30 second ads that reward players with one fraise. The option to watch these videos only occurs sometimes in the bottom right corner of the Shop. However, they are not available to every player. Whether or not one has that option is based on their location.
20 fraises can also be obtained by finishing 20 daily quests.