PREVIEW-Vinci 9-mths sales seen down 4 pct

* Vinci 9-mths sales, due Nov. 12 after market close

* Sales seen at 23.7 bln euro vs. 24.7 bln in 2008.

PARIS, Nov 10 (Reuters) - Vinci (SGEF.PA: Quote, Profile, Research), the world's largest construction and concessions group, is set to report nine-month sales down 4 percent at 23.71 billion euros ($35.52 billion), an average of six analysts polled by Reuters showed.

Vinci, which is due to report on Nov. 12 after the market closes, has already posted first-half sales down 3.2 percent, as the economic crisis hit the construction sector and the credit crunch put major infrastructure projects on hold.

Analysts expect the group to give an update on its construction and concessions division's prospects for 2009 and 2010.

Chief Executive Xavier Huillard has already said he expected the European contruction market to continue falling in 2010, and saw a 6 percent to 7 percent drop in 2009 full-year sales for its construction and energy divisions.

Analysts said the market will focus on the impact of the different stimulus packages implemented in countries where Vinci operates, and on the evolution of the flow of traffic on its motorways.

French rival Eiffage (FOUG.PA: Quote, Profile, Research) reported a forecast-lagging 1.1 percent drop in third-quarter sales earlier this month, as contruction of new offices in France remained weak. [ID:nL5433009]

Analysts are also awaiting an update on the Cegelec acquisition announced by Vinci at the beginning of September, which saw Qatar take a stake in the group's capital. [ID:nLV386535] ($1=.6676 Euro) (Reporting by Michel Rose and Gilles Guillaume; editing by Simon Jessop)