The NewsCorp-owned title avers that RTL has retained investment bank JP Morgan Chase to advise on a possible bid.
This is not the first time the two broadcasters have exchanged longing looks. Four years ago they were whispering sweet nothings into the others' ears – but without result.
RTL, controlled by Germany's BertelsmannGroup, operates more than 40 TV channels in ten nations, including the UK where it controls the Five channel.
The possibility of a merger that unites Five with Channel Four cannot be ruled out, observers believe – although such a move is unlikely to find favour with broadcast and competition regulators.
Data sourced from BBC Online (UK); additional content by WARC staff