Although there has been rapid growth in the use of the Internet around the world, many issues remain for the development of the online transactions. Many studies have shown that one of the inhibiting factors of online transactions is the lack of confidence in the seller. But, as the Internet itself is an open technology and not a familiar environment, online customers face another problem that results from the vulnerabilities of the Internet upon which e-commerce is based, and raises doubts about another type of trust: technological trust. Confidence in e-commerce request that the technical system and the partner are trustworthy. This study analyses the effect of online trust on online buying intention. More specifically, it investigates the impact of the two types of trust, online vendor trust and technological trust on intention to buy online. Moreover, we have compared this effect for Tunisians and French and to try to explain the differences, if any, according to Hofstede’s cultural dimensions. The study establishes the online trust as an important independent variable influencing intention to engage in online purchase transactions. The results suggest that for the French, only technological trust has an effect on intentions to buy online, even when they have previously buy online. For the Tunisians, Technological trust, vendor trust and previous online purchase influence intention to buy online. However, the results suggest that technological trust has the largest effect. The results also show that some of Hofstede’s dimensions of national culture may explain the differences between French and Tunisians.