Use as a tracer for marking liquid fuels and motor fuels of at least one compound of Formula I: where: - the benzene ring A is optionally substituted in at least one of the positions 2, 4 or 6 by: • a linear, branched or cyclic C 1 -C 18 alkyl radical, optionally substituted by at least one halogen and/or optionally interrupted by at least one oxygen; or • a linear, branched or cyclic C 1 -C 18 alkoxy radical, optionally substituted by at least one halogen and/or optionally interrupted by at least one oxygen; or • a linear, branched or cyclic C 2 -C 18 alkenyl radical, optionally substituted by at least one halogen and/or optionally interrupted by at least one oxygen; - the benzene rings B, C and D are substituted, independently of one another, in at least one ortho, meta or para position relative to the benzene ring A by: • a linear, branched or cyclic C 1 -C 18 alkyl radical, optionally substituted by at least one halogen and/or optionally interrupted by at least one oxygen; or • a linear, branched or cyclic C 1 -C 18 alkoxy radical, optionally substituted by at least one halogen and/or optionally interrupted by at least one oxygen; or • a linear, branched or cyclic C 2 -C 18 alkenyl radical, optionally substituted by at least one halogen and/or optionally interrupted by at least one oxygen; or • a halogen; at least one benzene ring B, C and D possibly comprising a 5 to 7-membered aliphatic ring fused thereto, provided that, when the benzene ring A is not substituted and the benzene rings B, C and D are each substituted by a methyl, the latter is not at para position relative to the benzene ring A. - the benzene ring A is optionally substituted in at least one of the positions 2, 4 or 6 by: • a linear, branched or cyclic C 1 -C 18 alkyl radical, optionally substituted by at least one halogen and/or optionally interrupted by at least one oxygen; or • a linear, branched or cyclic C 1 -C 18 alkoxy radical, optionally substituted by at least one halogen and/or optionally interrupted by at least one oxygen; or • a linear, branched or cyclic C 2 -C 18 alkenyl radical, optionally substituted by at least one halogen and/or optionally interrupted by at least one oxygen; • a linear, branched or cyclic C 1 -C 18 alkyl radical, optionally substituted by at least one halogen and/or optionally interrupted by at least one oxygen; or • a linear, branched or cyclic C 1 -C 18 alkoxy radical, optionally substituted by at least one halogen and/or optionally interrupted by at least one oxygen; or • a linear, branched or cyclic C 2 -C 18 alkenyl radical, optionally substituted by at least one halogen and/or optionally interrupted by at least one oxygen; - the benzene rings B, C and D are substituted, independently of one another, in at least one ortho, meta or para position relative to the benzene ring A by: • a linear, branched or cyclic C 1 -C 18 alkyl radical, optionally substituted by at least one halogen and/or optionally interrupted by at least one oxygen; or • a linear, branched or cyclic C 1 -C 18 alkoxy radical, optionally substituted by at least one halogen and/or optionally interrupted by at least one oxygen; or • a linear, branched or cyclic C 2 -C 18 alkenyl radical, optionally substituted by at least one halogen and/or optionally interrupted by at least one oxygen; or • a halogen; • a linear, branched or cyclic C 1 -C 18 alkyl radical, optionally substituted by at least one halogen and/or optionally interrupted by at least one oxygen; or • a linear, branched or cyclic C 1 -C 18 alkoxy radical, optionally substituted by at least one halogen and/or optionally interrupted by at least one oxygen; or • a linear, branched or cyclic C 2 -C 18 alkenyl radical, optionally substituted by at least one halogen and/or optionally interrupted by at least one oxygen; or • a halogen;