French advertising group Publicis said Monday it is to buy Boston-based marketing, communications and consulting firm Sapient for $3.7 billion.

Publicis said that once completed, the all-cash takeover agreed to by both sides will boost its digital and interactive services business to half of the group's total, and lead to higher revenue growth.

The combined group will have annual revenue above 8 billion euros ($10 billion) and more than 75,000 employees worldwide.

The deal comes six months after the collapse of Publicis' $35 billion merger with Omnicom Group, which had been touted as creating the world's largest advertising firm. The companies blamed an inability of their chief executives to agree on a balance of power in the merged company for the deal's collapse.

Paris-based Publicis runs its namesake agency as well as Leo Burnett Worldwide, Saatchi & Saatchi and DigitasLBi. Last month the group reported revenue growth for the first nine months of the year was only 1.5 percent, and said it expected it to remain about the same for the rest of the year.

Sapient employs 13,000 people at 37 locations around the world. It reported $1.36 billion in revenue for the 12 months to June 30, 2014.