£4 billion pounds of the sum would be paid to the British government in the form of a contribution to a fund to finance the clean-up of old nuclear reactor sites, the newspaper said.
The indicative all-cash offer amounts to almost 700 pence per share in the coveted British energy group, which declined to comment.
The report quoted "people close to the situation" as saying that RWE has been granted access to British Energy's data room to carry out due diligence. The German firm had less than €5.1 billion in net debt at the end of 2007, "giving it ample firepower for a deal," the newspaper said.
British Energy has also attracted interest from the French group EDF and Centrica of Britain, with the former estimated by Societe Generale as able to pay up to 760 pence per share, or a total of more than £12 billion.
German giant EON and the Spanish Iberdrola are also believed to be mulling bids for the British power company.