The combined Hopscotch and Sopexa business will have 700 employees globally, with annual sales of €210m and gross profit of €78m. The cost of the acquisition has not been disclosed.
Hopscotch, which is listed on the Euronext Paris stock market, first took a stake in Sopexa in 2016, when Paris-based events company Comexposium also acquired a share of around one third.
At the time, Hopscotch MD Frederic Bedin told PRWeek the "alliance" would enable it to compete with the big "Anglo-Saxon" networks for global accounts.
Hopscotch and Sopexa have worked together on projects including the latest edition of the Barilla Pasta World Championship, in which teams from both agencies created the concept and managed media and influencer relations.
They also undertook joint work on the creation of the Foundation for Innovation and Transmission of Taste, which provides funding and support so people from all walks of life can have access to healthy, delicious, high-quality food.
Bedin said: "We are very happy to once again be able to capitalise on the strengths that Hopscotch and Sopexa share. Together, we will cover all of the key business sectors (tech, automotive, luxury, banking/insurance, industry, healthcare, food and others), as well as the full range of communications activities, from digital media to events to public relations and shopper experience."
In April, two unnamed Hopscotch representatives were appointed to the Sopexa board of directors.
PRWeek asked Hopscotch if it has bought the share of Sopexa that was previously owned by Comexposium but had not received a reply at the time of publication.