The invention relates to an autoinjector comprising a body (1010； 2010) that receives a barrel, said barrel containing fluid product and comprising a plunger and a needle, such as a pre-filled syringe (A). The autoinjector comprises an actuator sleeve (1011； 2011) having a contact end intended to come into contact with the user's body, which actuator sleeve (1011； 2011) can be moved in relation to the body that receives the barrel (1010； 2010) between projecting positions, in which the actuator sleeve (1011； 2011) projects at least partially from the barrel-receiving body, and an actuation position, in which the actuator sleeve (1011； 2011) is moved axially into the barrel-receiving body, said actuator sleeve (1011； 2011) occupying a first projecting position prior to actuation of the autoinjector and a second projecting position following actuation of the autoinjector. Either the actuator sleeve (1011； 2011) or the body that receives the barrel (1010； 2010) comprises a flexible tab (1110； 2110) that can deform laterally in relation to the actuator sleeve (1011； 2011) and/or in relation to the body that receives the barrel (1010； 2010) when the actuator sleeve is moved from the first projecting position into the actuation position and subsequently from the actuation position back into the second projecting position.Autoinjecteur comportant un corps (1010； 2010) recevant un réservoir, ledit réservoir contenant du produit fluide et comportant un piston et une aiguille, tel qu'une seringue pré-remplie (A), ledit autoinjecteur comportant un manchon actionneur (1011； 2011) comportant une extrémité de contact destinée à venir en contact avec le corps de l'utilisateur, ledit manchon actionneur (1011； 2011) étant déplaçable par rapport audit corps recevant un réservoir (1010； 2010) entre des positions projetées, dans lesquelles ledit manchon actionneur (1011； 2011) fait au moins partiellement saillie hors dudit corps recevant un réservoir (1010； 2010), et une position d'act
