(Corrects year of Sanofi merger with Aventis to 2004 from 2001
in paragraph 14)

* Accountant with 20 yrs experience seen cautious on price

* Targeting Genzyme fits within disciplined M&A strategy

* Viehbacher on mission to make drugmaker more international

By Ben Hirschler and Caroline Jacobs

LONDON/PARIS, July 29 (Reuters) - After 20 months in the
job, Sanofi-Aventis Chief Executive Chris Viehbacher is hungry
for a deal -- but Genzyme investors looking for a rich pay-out
can expect him to play a careful hand.

The 50-year-old dual German-Canadian national has been
around the block a few times in the drugs industry. He spent 20
years at GlaxoSmithKline before being passed over for CEO at the
British group following a close fight.

He jumped ship in 2008 to become the first non-French CEO at
Sanofi's headquarters on the banks of the Seine in Paris.

A relaxed and easy talker, he has plenty of fans among
investors who see him as an catalyst for needed change at
Sanofi. The deft handling of his own career also shows a shrewd
operator at work.

Viehbacher made clear on Thursday he was not going to
overpay for acquisitions, while declining to comment on specific
deals, after sources familiar with the matter said Sanofi was
readying a bid of up to $18.7 billion for U.S. biotech firm
Genzyme.

Industry watchers say he has picked his target carefully by
zeroing in on an asset with problems that are soluble, but may
deter other bidders, and a price tag that fits his budget.

"I would put him at the more cautious end of the spectrum
when it comes to M&A," said Ben Yeoh, an industry analyst at
Atlantic Equities.

"Genzyme is something of a special case because they've
struggled to resolve their manufacturing problems and one could
argue that an outside player might do a better job."

One banker said Viehbacher -- a chartered accountant by
training -- was anxious not to repeat the mistake of European
rival AstraZeneca, which was accused of overpaying for another
U.S. biotech company, MedImmune, in 2007.

Since arriving at Sanofi he has been on a mission to inject
an Anglo-Saxon culture into a bastion of French business.

"SMILING KILLER"

He has overhauled research and development -- ditching many
products in the process -- and slashed the layers of the research
department to six from 11.

Some employees have dubbed him the "Smiling Killer" because
of plans to shed 4,000 positions by 2013. But he has scored well
with the investment community, which has appreciated his clear
talking and down-to-earth strategy, including a targeted focus
on external growth as one of the company's top three priorities.

So far, those external deals have come in the form of
licensing agreements and small acquisitions in consumer health,
emerging markets, vaccines and licensing deals.

Buying Genzyme would be in a different league and the
biggest deal for Sanofi since its merger with Aventis in 2004.
Yet it would still fit into Viehbacher's oft-repeated game plan
of making acquisitions worth up to $20 billion in market value.

Some analysts question whether giving clear guidance on deal
size could box Viehbacher in to a sub-optimal transaction.

"I'm afraid if he's limiting himself to things that are not
more than $20 billion then it's quite hard to see he's going to
buy something that will make enough of a difference," said Paul
Diggle, an industry analyst at Ambrian Partners.

"Genzyme's not a bad fit for them but even if Genzyme
returns to full profitability and makes a net contribution
fairly quickly, it's not going to be enough to really give
Sanofi the growth it is hoping for. It is part of the solution."

Last year, Viehbacher did more than 30 bolt-on transactions
worth about $9 billion. This year he has done only $3 billion to
date -- arguably leaving headroom for a larger deal.

Viehbacher has had plenty of pitches from bankers offering
opportunities. With a well-flagged "cliff" of looming drug
patent expiries and strong cash position, Sanofi has long been
touted as an obvious buyer of smaller drug companies.

He has bided his time, but he has also built close ties with
a few external advisers.

He is being advised on Genzyme by Evercore Partners -- the
same firm that handled Sanofi's animal health tie-up with Merck
& Co -- and has lined up financing from banks including JP
Morgan and BNP Paribas, according to banking industry sources.

Genzyme is being advised by Goldman Sachs and Credit Suisse
, the sources added.

Married with three children, Viehbacher is fluent in French,
English and German.
(Additional reporting by Jessica Hall in Philadelphia; Editing
by Andrew Callus)