* Havas H1 net profit up 22.5 percent to 49 million eur
* Organic growth 1.8 percent in H1, 2 percent in Q2
* Lower growth rate than major competitors
* Margin rose by 1.3 points to 11.5 percent in H1
PARIS, Aug 31 (Reuters) - Advertising group Havas on Tuesday posted an improvement in first-half operating margin even as its organic growth rate came in lower than that of its competitors.
The sixth-largest advertising group in the world said its operating margin for the first half rose 1.3 points to 11.5 percent thanks to cost-cut measures introduced last year, despite growth slowing in the United States in the second quarter.
It achieved like-for-like organic growth of 1.8 percent in the first half, below the 2.5 percent Britain's WPP posted last week. WPP, the world number one advertising group by sales also raised its full-year targets. In the second quarter, Havas posted 2 percent organic growth, against 7.1 percent for France's Publicis and 6 percent for U.S.-based Omnicom.
The group, whose president and main shareholder is billionaire financier Vincent Bollore, also head of the Bollore group, did not give any targets for the year as a whole.
In France, the group saw a 1.6 percent dip in sales the first half, suffering from the impact of losing Carrefour's account to Publicis in 2009. The impact of this loss was fully absorbed by the end of June, it said.
Without the Carrefour effect, organic growth in France would have reached 4 percent in the first half, Havas said.
(Reporting by Cyril Altmeyer; Writing by Helen Massy-Beresford; Editing by Erica Billingham)