Mouche, also known as Lanterlu, is an old, French, trick-taking card game for two to six players which has elements, such as bluffing, reminiscent of the much later game of poker. It is a member of the Rams family of games and, although it is a gambling game, often played for small stakes, it is also suitable as a party game or as a family game with children from the age of 12 upwards. It is named after the mouche, a term that variously refers to its winning hand, the basic stake and the penalty for failing to take any tricks. Although also called Bête, it should not be confused with the older game of that name from which it came and which, in turn, was a derivative of Triomphe.

Mouche is first recorded in the Académie Universelle des Jeux of 1718, although Parlett implies that, from its terminology, it ought to be an ancestor of the English game, Lanterloo, which goes back at least to Cotton's rules of 1674, and that they are probably both descended from an early trump game, known as Triomphe. In the early 18th century, Mouche was considered a "most pleasant" provincial game that had yet to catch on in Paris. In the mid-19th century, it is described as being "very like Triomphe in the way it is played, but much more spicy" and as a game for the "petty bourgeoisie", a family game played before dinner.

Mouche also went under the less fashionable name of Bête ("Beast") in the region of Perche and its surrounding areas. However, Bête or Beste is also the name of an earlier, possibly antecedent, game in which there is no equivalent of the flush known as the mouche, but otherwise the rules are much the same. The term bête came to be used in both French and German as the name of the stake and penalty payment in a number of old games of this type and may be the origin of the word bet which dates to the same era. Another name for Mouche was Lanterlu, a term clearly related to the Lanterloo, although in the English game the Jack of Clubs is the top trump, a concept not found in Mouche but mirrored in its descendant, Mistigri, historically also known as Pamphile.

The following rules are based on van der Aa (1721) with some additional clarifications from the Académie des Jeux Oubliés.

The game is played by three or four players using a pack of 32 French-suited cards. If three play, the Sevens are removed. The cards follow the Écarté scheme, ranking from highest to lowest as follows: K Q J A 10 9 8 7.

Tokens or chips are used for scoring. According to the Academie des Jeux Oubliés, at the start of the game each player takes 20 jetons (round), 16 fiches (long rectangular) and 9 contrats (short rectangular). A fiche was worth 5 jetons and a contrat was worth 100 jetons.

The first dealer is chosen by lot; the player drawing the agreed card (e.g. a King) dealing first. Deal and play are anti-clockwise. The dealer antes 5 jetons to the pot before dealing each player five cards. These may be dealt either as 2+2+1, 3+2, 2+3 or 2+1+2 as the dealer wishes, but the method should not be changed during a game. The dealer then turns the next card as trumps leaving it face up on the table, and places the remaining cards face down to form the talon.

Players then decide whether they will pass, exchange a number of cards from one to five or 'stick' with the cards in their hand. If they pass, they just lay their hand, face down, on the table and take no further part in the deal. If they want to exchange cards, they select their discards and place them face down on the table announcing the number of cards being exchanged e.g. "all cards", "four cards", etc. The dealer then places the discards on the table face to his right and gives the player the same number of cards from the top of the talon.