The deal amounts to it buying nearly eight million shares of ORPEA at a price of 40.34 euros per share, or a total of 320.8 million euros, the CPPIB said Wednesday.
It also plans to underwrite a primary share capital increase of up to 100 million euros to help the company grow its business.
Paris-based ORPEA was founded in 1989 and provides nursing, post-acute care, rehabilitation and psychiatric services in France, Belgium, Spain, Italy and Switzerland.
“ORPEA has a demonstrated track record of exceptional client service, balanced with strong operational and financial performance," said Scott Lawrence, CPPIB's vice-president and head of relationship investments.
"We believe in, and will actively support, ORPEA’s strategic goals with respect to geographic expansion and growth within its current markets, and that the alignment of those goals with CPPIB's long-term investment objectives will help foster future success."
The CPPIB, one of the world's largest pension funds, invests money not needed by the Canada Pension Plan to pay benefits for some 18 million current and retired contributors.
CPPIB had net assets of $192.8 billion as of Sept. 30, up from $188.9 billion at the end of the previous quarter.