Under the agreement, the company says shareholders will receive US$6 per subordinate voting share.
Shares in the company were up $2.72 at $7.18 in trading on the Toronto Stock Exchange after the deal was announced.
Exfo makes test, monitoring and analytics equipment for the communications industry.
As of Monday, Mr. Lamonde, who serves as Exfo’s executive chairman, controlled, directly or indirectly, nearly 3.7 million subordinate voting shares representing 14.2 per cent of the issued and outstanding subordinate voting shares.
Mr. Lamonde also controlled all of the issued and outstanding multiple voting shares for a total of 61.5 per cent of the company’s shares and 93.5 per cent of the voting rights.