A connection member (100A, 100B) intended to be used for the assembly of metal tubes to form a demountable metal frame of a relocatable building, in particular a farm building, the connection member (100A, 100B) comprising a first part of the connection member (110A, 110B) and a second part of the connection member (120A, 120B) which are designed to be removably assembled by removable fastening means at a first assembly operation, wherein: - the first part of the connection member (110A, 110B) comprises a first guide channel and a second guide channel, - the first guide channel being intended slidingly to receive an end part of a first metal tube, - the second guide channel being intended slidingly to receive an end part of at least one second metal tube, the second guide channel being positioned substantially perpendicular to a central portion of the first guide channel, - the second part of the connection member (120A, 120B) comprises a third guide channel having a transverse through opening, - the third guide channel being intended, together with the second guide channel, slidingly to receive an end part of at least the second metal tube, - the transverse through opening being intended, together with the first guide channel, slidingly to receive an end part of the first metal tube and wherein: - the first guide channel, the second guide channel and the third guide channel each have a U-shaped cross-section or similar with a web bordered by two opposite-facing side flanges (114, 115, 116, 117, 123, 124) and also wherein, at the first assembly operation: - the connection member (100A, 100B) is designed to surround the first metal tube and the at least one second metal tube, so that: - the opposite-facing side flanges (123, 124) of the third guide channel cover all or part of the opposite-facing side flanges (116, 117) of the second guide channel, and - the transverse through opening extends opposite all or part of the central portion of the first guide channel. - the first part of the connection member (110A, 110B) comprises a first guide channel and a second guide channel, - the first guide channel being intended slidingly to receive an end part of a first metal tube, - the second guide channel being intended slidingly to receive an end part of at least one second metal tube, the second guide channel being positioned substantially perpendicular to a central portion of the first guide channel, - the second part of the connection member (120A, 120B) comprises a third guide channel having a transverse through opening, - the third guide channel being intended, together with the second guide channel, slidingly to receive an end part of at least the second metal tube, - the transverse through opening being intended, together with the first guide channel, slidingly to receive an end part of the first metal tube - the first guide channel, the second guide channel and the third guide channel each have a U-shaped cross-section or similar with a web bordered by two opposite-facing side flanges (114, 115, 116, 117, 123, 124) - the connection member (100A, 100B) is designed to surround the first metal tube and the at least one second metal tube, so that: - the opposite-facing side flanges (123, 124) of the third guide channel cover all or part of the opposite-facing side flanges (116, 117) of the second guide channel, and - the transverse through opening extends opposite all or part of the central portion of the first guide channel.