A bellows, intended to cover a mechanical joint, the bellows comprising a cylindrical and corrugated side wall, extending about a longitudinal axis, the side wall comprising: - an alternation of crests (4 n) and of troughs (3 n), forming corrugations (2 n), each corrugation being formed by two crests extending on either side of one and the same trough, the crests being closer to the longitudinal axis than the trough; - flanks (5 n,1, 5 n,2), each flank extending between a crest and a trough, each corrugation (2 n) comprising a first flank (5 n,1) and a second flank (5 n,2) that are opposite, separated by a same trough (3 n); the side wall being flexible, such that two adjacent crests (4 n, 4 n+1) and/or two adjacent troughs (3 n, 3 n+1) can converge or move apart from one another, in a direction parallel to the longitudinal axis; the bellows being characterized in that it comprises an elementary electrical circuit (8 n) associated with a corrugation (2 n), or a plurality of elementary electrical circuits, respectively associated with different corrugations, the or each elementary electrical circuit comprising: - a first conductive element (6 n,1) and a second conductive element (6 n,2), extending along the first flank (5 n,1) and/or the second flank (5 n,2) of the corrugation, along an inner face (2 i) of the side wall, the first conductive element being separated from the second conductive element; - a first conductive track (7 n,1) and a second conductive track (7 n,2), linked respectively to the first conductive element (6 n,1) and to the second conductive element (6 n,2); the or each elementary electrical circuit being such that: - the first conductive track and the second conductive track are connected, or configured to be connected, to a detector of closure of the elementary electrical circuit (9 n, 9), such that when an electrically conductive liquid extends from the first conductive element (6 n,1) to the second conductive element (6 n,2), the closure of the elementary electrical circuit is detected. - an alternation of crests (4 n) and of troughs (3 n), forming corrugations (2 n), each corrugation being formed by two crests extending on either side of one and the same trough, the crests being closer to the longitudinal axis than the trough; - flanks (5 n,1, 5 n,2), each flank extending between a crest and a trough, each corrugation (2 n) comprising a first flank (5 n,1) and a second flank (5 n,2) that are opposite, separated by a same trough (3 n); the side wall being flexible, such that two adjacent crests (4 n, 4 n+1) and/or two adjacent troughs (3 n, 3 n+1) can converge or move apart from one another, in a direction parallel to the longitudinal axis; the bellows being characterized in that it comprises an elementary electrical circuit (8 n) associated with a corrugation (2 n), or a plurality of elementary electrical circuits, respectively associated with different corrugations, the or each elementary electrical circuit comprising: - a first conductive element (6 n,1) and a second conductive element (6 n,2), extending along the first flank (5 n,1) and/or the second flank (5 n,2) of the corrugation, along an inner face (2 i) of the side wall, the first conductive element being separated from the second conductive element; - a first conductive track (7 n,1) and a second conductive track (7 n,2), linked respectively to the first conductive element (6 n,1) and to the second conductive element (6 n,2); - a first conductive element (6 n,1) and a second conductive element (6 n,2), extending along the first flank (5 n,1) and/or the second flank (5 n,2) of the corrugation, along an inner face (2 i) of the side wall, the first conductive element being separated from the second conductive element; - a first conductive track (7 n,1) and a second conductive track (7 n,2), linked respectively to the first conductive element (6 n,1) and to the second conductive element (6 n,2); the or each elementary electrical circuit being such that: - the first conductive track and the second conductive track are connected, or configured to be connected, to a detector of closure of the elementary electrical circuit (9 n, 9), such that when an electrically conductive liquid extends from the first conductive element (6 n,1) to the second conductive element (6 n,2), the closure of the elementary electrical circuit is detected. - the first conductive track and the second conductive track are connected, or configured to be connected, to a detector of closure of the elementary electrical circuit (9 n, 9), such that when an electrically conductive liquid extends from the first conductive element (6 n,1) to the second conductive element (6 n,2), the closure of the elementary electrical circuit is detected.