* Ad market showing stabilisation signs in Sept
* Premature to speak of ad market recovery, Q4 is key
* No change in JCDecaux Q3 sales guidance
* Shares hit session low of 14.94 euros after comments
(Adds details, adds M6 forecast)
By Dominique Vidalon
PARIS, Oct 14 (Reuters) - The global advertising market showed signs of stabilisation in September, notably in France and China, but it is too early to speak of an upturn, the co-chief executive of JCDecaux said on Wednesday.
Jean-Charles Decaux told Reuters the world's No. 2 outdoor advertising group had no reason to change its outlook for the third quarter.
"What we are clearly seeing are signs activity is stabilising. It would be premature to speak of a real market recovery," Decaux said.
"But in developed countries such as France and even in emerging countries like China, we see a business trend in September that is showing a sharp improvement from the first half," he added.
The fourth quarter would be "key" to assess if "we go from a deterioration to a stabilisation and a recovery or if we stabilise at a low point", he said.
JDecaux shares traded at 15.34 euros before the comments. They hit a session-low of 14.94 euros after the news emerged. By 1059 GMT, the shares were quoted up 1.34 percent at 15.09 euros, underperforming the European media stocks.
Separately, M6 Executive Chairman Nicolas de Tavernost told Reuters on Wednesday that the bleak period for TV ad sales was over but that this was "no cause for euphoria".
JCDdecaux, which competes for budgets with world leader Clear Channel Outdoor, has forecast a third-quarter sales fall in line with the 13.8 percent drop suffered in the first half of the year.
It has not given an outlook for the full year, other than to say it expected 2009 to be a negative year for sales.
JCDecaux has been hit hard by the global economic downturn, which is severely pressuring corporate advertising budgets. Its peers have also forecast a weak advertising outlook. Last week, Maurice Levy, chief executive of French advertising group publicis, told Reuters there had been a small upturn in the advertising market in September, with conditions seeing a "slow and steady" improvement.
The global advertising market could drop by around 10 percent this year, he predicted.
JCDecaux, which last month raised its holding in German outdoor advertising company Wall AG to 90.1 percent from 40 percent previously, will pursue its "selective" acquisition policy, he said.
But the purchase of the U.S. assets of Clear Channel Outdoor or of CBS Outdoor was not on the group's agenda. (Additional reportng by Cyril Altmeyer) (Editing by David Cowell)