By Leila Abboud and Jennifer Saba NEW YORK/PARIS (Reuters) – Shares in French online advertising firm Criteo rose more than 30 percent in its stock market debut on Nasdaq on Wednesday, showing investor appetite for technology start-ups and delivering a payday to its venture capital backers. Shares in the company, which uses tracking technology to target ads at consumers surfing the web, opened at $31 and were at $41.40 by 1625 GMT, giving the eight-year old start-up a market capitalization of roughly $2.3 billion. The sale of 8.08 million shares raised $250 million for the Paris-based company that will be used to fuel its international expansion and growth. The success of Criteo’s share sale is a sign of investor interest in technology listings against the backdrop of a broader rally of the SP 500 information technology index and just weeks before the much-anticipated market debut of social network Twitter.