Feb 8 (Reuters) - Publicis, the world's largest advertising group by market value, said on Thursday it expects organic net revenue to grow by 4% to 5% in 2024, after delivering a fourth quarter above expectations, bolstered by an acceleration in activity in its Media segment and high demand in first-party data.

"In a very challenging macroeconomic context, and after 6 years of transformation, Publicis definitely extracted itself from the pack in 2023," CEO Arthur Sadoun said in a press release.

Competitor WPP said in January that 2024 would be another tough year, forecasting roughly flat like-for-like growth of 0% to 1%.

Publicis said it expects an 18% operating margin for the year, which includes a 100 million euro ($107.62 million)investment in its plan to integrate artificial intelligence, or AI, further into its platform model, as announced in January.

Sadoun said the group remains aware of macroeconomic difficulties and their impact on customers' businesses in 2024.

"We anticipate cuts here and there in traditional marketing," the CEO said during a press call. "On the other hand, we're very confident that we can continue to maintain our momentum."

For the first quarter, the maker of marketing campaigns for the likes of L'Oréal or Walmart anticipates an organic growth within the full-year range.

Net revenue came in at 3.54 billion euros in the fourth quarter, a 5.7% organic growth in line with the 5.5% to 6% guidance range announced in October.

A ramp-up in new business in Publicis' Media segment as well as high demand for first-party data accounted for the group's strong quarterly performance, it said in a release.

The group will put aside between 700 million and 800 million euros this year for potential mergers and acquisitions to boost its data, tech and AI capabilities, it said. Another 200 million will be earmarked for a planned share buyback.

Publicis' investments in data and tech via units like Epsilon and Sapient have led to strong performances in the past quarters, positioning the group as an outlier in the advertising industry. ($1 = 0.9292 euro) (Reporting by Stéphanie Hamel; additional reporting by Olivier Sorgho; editing by Jonathan Oatis)