Final answer:
France aimed to expand their commercial interests and political power in Southeast Asia by accessing natural resources like spices, embarking on a broader European trend of imperialism driven by economic gains.
Step-by-step explanation:
One reason France wanted to establish colonies in Southeast Asia was to gain access to resources such as spices.
During the period of European colonization, nations such as France sought to establish colonies to enhance their economic and political power. France's central interest in Southeast Asia, particularly in what became known as French Indochina (comprising of today's Vietnam, Laos, and Cambodia), was to expand their commercial and political influence through control of valuable natural resources like spices, which were highly coveted in Europe for their rarity and value.
This motive is similar to the Portuguese's drive for the spice trade in an effort to enrich the nation and diminish the Muslim's control over it, thus bolstering the Christian world. Spices represented a luxury that only the wealthy could afford, and by establishing a direct trade route, European powers could control and profit significantly from the trade. France's colonial activities in Southeast Asia were part of a broader trend of imperialism driven by economic interests, where colonies were seen as essential sources of wealth.