This high-speed door is provided for closing a bay made in a wall (4) delimited by a lintel and by two vertical sides. The door comprises: two lateral parts placed in an essentially vertical manner against each of the vertical sides of the bay; a shaft (12) positioned at the level of the lintel of the bay and rotationally driven by electromechanical means, and; a curtain (7) made of a flexible material having a first side (7a) and a second side (7b), joined to the shaft (12), the rotation of the shaft (12) being able to move the curtain (7) between a closed position in which the curtain (7) closes the bay and an open position in which the curtain (7) opens the bay. In addition, the door comprises flexible means for protecting the shaft (12) which extend between the two lateral parts (2) and (3) and which are capable of coming in contact with the lintel, the flexible protecting means also having first transversal sealing means that can come in transversal contact with the first side (7a) of the curtain (7) when it is in a closed position.