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* Europe remains weak spot
* Tweaks annual organic growth target to 3.6 pct
* Q2 organic sales growth 5 pct
* H1 sales rise 8.7 pct to 3.35 bln eur
* H1 op profit 462 mln eur vs poll avg 440 mln
* Operating margins rise to 13.8 pct
By Leila Abboud
PARIS, July 18 (Reuters) - France's Publicis saidthe pace of sales growth accelerated sharply to 5 percent in thesecond quarter, helped by robust demand for online marketingservices and strength in North America.
The world's third-biggest advertising agency narrowed itsannual target for organic growth to 3.6 percent from between 3.2and 3.6 percent.
The pick-up seen at Publicis, which comes after a relativelyslow first quarter, may bode well for the results of marketleader WPP and number two Omnicom, due in thecoming weeks.
Market researchers have predicted global advertising spendwill growth 3 to 3.5 percent this year.
Publicis shares were up 2.9 percent at 59.34 euros by 0732GMT, the biggest gainers on France's blue-chip CAC 40 index.
"Organic growth is back to levels that make investorscomfortable about the sustainability of margin expansion," saidClaudio Aspesi, an analyst at Bernstein Research.
"The stock has already done very well in 2013, but withimproving performance and outlook it is natural that investorswill like the story even better."
First-half sales rose 8.7 percent to 3.35 billion euros($4.39 billion), in-line with analysts' expectations. Revenuewas 1.79 billion in the second quarter.
Operating profit rose 11.6 percent to 462 million euros,ahead of the Thomson Reuters I/B/E/S average of 440 million.
The operating margin was 13.8 percent in the half, animprovement from last year's 13.4 percent, helped by continuedcost cuts in everything from real estate to technology.
Growth was strong in North America and emerging markets,including Brazil, China, India and Russia, while European salescontracted by 1.1 percent in the second quarter.
"The results are good but it has not been easy and we mustremain vigilant since there is a lot of uncertainty in the worldeconomy," said Publicis Chief Executive Maurice Levy.
"Emerging markets are in slight retreat, the U.S. is holdingup well, while Europe remains in search of growth."
Levy said most sectors, including autos, banks, telecoms andtechnology, and consumer goods, had maintained or boostedmarketing budgets in the second quarter.
DIGITAL PAY-OFF
The exception was Publicis' healthcare business, which hasshrunk in recent quarters because of big pharma companies'struggles with patent expiries and slow new drug approvals.
Levy said the pharma business would likely return to growthin the third quarter, however.
Across the board, major companies spent more on so-calleddigital advertising and services than old-fashioned print andtelevision ads, Levy said.
Boosted by a billion euros of acquisitions in the past twoyear, the agency has expanded into social media services, buyingad space for brands online in real-time auctions, and designingcampaigns for the web.
Publicis said it now earns almost 37 percent of sales fromsuch digital activities.
Its larger rival WPP is also well positioned in the area.
Bernstein's Aspesi wrote in June that WPP and Publicis had"significant leadership positions" in both emerging markets anddigital, giving them an advantage over U.S. peers Omnicom andInterpublic Group.
Publicis shares have risen 28 percent this year to close at56.57 euros on Wednesday, compared with a 14 percent rise forthe Stoxx 600 European Media index.
