1) The French originally tried settling close to Spain but were wiped out, forcing them to settle in the safer northern latitudes of North America. The fur trade became crucial to sustaining the French colonies.
2) The French allied with some Native American tribes but made enemies of the Iroquois Confederacy, leading to frequent raids that disrupted French fur trading.
3) Disease and violence escalated in the mid-17th century as the Iroquois launched genocidal attacks, destroying French colonies and other Native villages to replenish their own declining population. The French colonies struggled to be profitable and yielded little return for the investment.