But the French government is expected to resist Novartis' advance, faced with the possibility that Sanofi itself could be at risk of a takeover if it fails in its attempt, leaving the country with no top-tier drug companies.
The Swiss firm stressed that it was merely 'exploring the feasibility' of a link-up at present, but simply by throwing its hat into the ring it has raised pressure on Sanofi to raise its offer and turn the process into an auction.
Sanofi has made an offer of around €48 billion, and Aventis chief executive Igor Landau has said that Sanofi would need to increase its bid by 40 to 50 per cent before Aventis would consider a deal. Speculation among analysts has been that Novartis may be prepared to offer in the region of €70 million.
A Novartis/Aventis merger would create a powerhouse in three lucrative and fast-growing therapeutic categories - cardiovascular, diabetes and oncology - and has the added advantage of a strong position in the important (and fastest-growing) US market. One of the major criticisms of the Sanofi bid is that while the opportunities for cost savings are good, it will not address the issue of growing US market share.
And the opportunities for cost-cutting between Novartis and Aventis are also good, according to Swiss broker Lombard Odier Darier Hentsch.
However, it is not expected that Novartis chief executive Daniel Vasella will make an early announcement of a bid, as he has plenty of time for 'watchful waiting' as wrangles between Sanofi and Aventis over the legality of the takeover attempt rumble through the courts. A verdict on these issues is not expected until May.
Meanwhile, Aventis looks set to face a new patent challenge on its blockbuster cardiovascular drug Lovenox/Clexane (enoxaparin) in the US from Momenta Pharmaceuticals. Interestingly, Momenta is partnered on the enoxaparin project with none other than Novartis' generics unit Sandoz.
A merger with Aventis would give Novartis the branded enoxaparin market - valued at €1.7 billion in 2003 - as well as an inroad into the generic market for the drug. Other companies challenging the enoxaparin patent estate in the US include Teva and Ampastar.
But the prospect of renewed consolidation in the pharmaceutical industry can only test the nerves of suppliers to the sector as they face a further shrinking of their traditional customer base.