The company, which does not split off PR revenues in its results statements, saw revenues of €765m during the first six months of the year, compared with €729m during the same period in 2010.
There was also a significant rise in 'income from operations', climbing 13% to €95m.
David Jones, CEO Havas, said : 'Havas had a good first half 2011: We delivered solid improvements in profitability, achieving an increase in margin of 90 basis points compared with the same period last year, to reach one of the highest margins in the sector at 12.4%.'
'Our dedicated efforts to improve operational efficiencies have borne fruit and debt reduction has proceeded apace, with average net financial debt standing at just €22m.
'Havas now has a strong balance sheet structure and is in a good position to capitalise on new growth opportunities, but similarly is agile and entrepreneurial enough to respond to any changes driven by economic uncertainty.'
The group's UK revenues were flat, behind the average organic growth across Europe of 1.3%.
The overall 5.6% revenue rise was underpinned by performance in North America (8.1% growth), Asia Pacific (9.2%) and Latin American (24.6%).
Havas added that it had won net new business worth €940m during the first half of the year.