A clasp having deployant blades for a wristband includes at least two blades (1, 2), one movable blade (1) being articulated on a second blade (2) in the area of first extremities, the clasp being able to adopt (i) a first closed configuration, in which the movable blade (1) exhibits a first predefined form (C1) and extends in a continuous manner for its entire length, substantially along the surface of the second blade (2); and the second extremity of the movable blade (1) is maintained in position by the clasp, and (ii) a second, deployed configuration, in which the second extremity of the movable blade (1) is free, and the movable blade (1) is able to exhibit a second predefined form (C2), different from the first predefined form (C1), in order to optimize the passage surface for the hand of a person wearing the clasp.