The Anglo-Dutch giant announced in August its intention to cut 20,000 jobs, 11 per cent of its workforce, by 2010 and pursue growth by focusing on its core businesses.
Unilever expects the Boursin business to record sales of €100m in 2007, which is a quarter of the selling price agreed with Le Groupe Bel.
Commenting on the sale Keesvan der Graaf, president of Unilever Europe, said: "Having taken the decision to focus our portfolio on priorities outside the cheese category, I am confident we have a found a new owner that will offer further growth and brand development opportunities for Boursin."
Boursin makes half of its sales in France and the remainder in the rest of Europe, North America and Asia.
The brand's Garlic & Fine Herbs, Pepper and other cheese varieties are produced in Pacy, France, where the majority of Boursin's 150 employees are based.
Le Groupe Bel, which also owns the Babybel and Laughing Cow brands, is taking on Boursin's employees as part of the sales agreement.
"We are delighted with the acquisition of an iconic brand like Boursin," said the CEO of Le Groupe Bel, Gerard Boivin.
"We are extremely optimistic about our ability to grow both sales and market share."
The deal is expected to be completed in the next two to three months and is subject to regulatory approval and consultation with employee representatives.
The sale of Boursin is another step in Unilever's plan to lift its margins beyond 15 per cent by 2010 by making €2bn worth of divestments, 20,000 job cuts and enacting various other cost cutting measures.
The company is looking to achieve strong growth and improved margins by focusing on its strongest performing core businesses.