A coupling device for sealingly coupling a first wall defining a flexible pipe (11) to a tubular nozzle (9) of a connector (1) in a biopharmaceutical assembly, the coupling device including the connector (1) including the tubular nozzle (9), on which one end of the pipe can be inserted along an axis A, a plurality of flexible tabs (3) extending from an intermediate area (7) of the coupling body toward the free end (1a) of the nozzle, an abutment clamp (16), a connection interface (6), a separate ring (2), axially movable between an inoperative position and an operative position, for covering the flexible tabs (3) such as to push same radially inward in order to press the pipe onto the nozzle in the operative position, the tabs extending substantially parallel to the axis (A) when the ring (2) is in the operative position.