Bollore bought the stock late last week after Harris announced its financial results. Harris reported annual revenue up 13% while pro forma organic revenue had dropped 1%.
Greg Novak, president and CEO of Harris Interactive, said the decline was due to the "rapid deterioration of the macro-economic environment in North America" which has hit the firm's pharmaceutical business particularly hard.
In the past year, Harris share prices have fallen from around $4 to $1.40, which Bollore has made the most of by increasing his shareholding from around 6% to 12.89%.
This month alone, while shares hit new lows, he snapped up nearly $500,000 of the company's stock.
Bollore is also a major shareholder in Synovate-parent the Aegis Group and has been trying to gain representation on its board for the past two years.
Earlier in the year, Bollore took full control of French opinion polling and market research group CSA-TMO, in a move to strengthen his presence in the market research sector.