The Financial Times this morning said that sources close to Bollore claim that Publicis Groupe, headed by chief executive Maurice Levy, is interested in taking the stake and is arguing to keep Havas in French ownership.
Speculation that Havas could be taken over has been increasing ever since the company lost out in the battle for Grey Global Group to WPP Group.
This has only intensified with Bollore continuing to up his stake in Havas, with his most recent purchase last week taking his holding to some 15%.
In an interview with French business magazine La Vie Financiere, Levy said: "As far as I know, the group is not for sale. If it were the case one day, we would of course look at the matter."
But with Havas' prize asset of the Media Planning Group at stake, Publicis would almost certainly find itself battling against the WPP Group in any such deal.
French pride has been pricked after losing three takeover battles in the advertising sector to British-owned WPP. Havas lost out in 2001 in the battle to take control of Tempus, and last year Publicis Groupe lost the fight for Cordiant Communications.
The FT reports that there is likely to be widespread support for Publicis taking control of Havas if it was to go up for sale, with the French government previously showing a wish to keep local businesses from foreign ownership. However, client conflicts could make it impractical.
If you have an opinion on this or any other issue raised on Brand Republic, join the debate in the .