Colour–magnitude relations along the D3-43 candidate cluster line of sight. Small black dots are the CFHTLS galaxies. Upper figure: red disks are the spectroscopically confirmed members of S3, blue circles are the S1 members, green squares are the S2 members, pink triangles are the S4 members. The inclined red line is the tentative red sequence for structure S3 early-type galaxies. Lower figure: red circles are the S3 substructure #1 members, blue disks are the S3 substructure #2 members (see text for details). The inclined red line is the tentative red sequence for S3 early-type galaxies.