Early settlements in America would have needed to be along waterways because of their ships. The supplies they brought with them were on the ship, plus if the motherland had sent an annual resupply then it would’ve been easier to access the colonists if they were near the shore.
Also France was interested in economic growth so when they didn’t find gold and silver in Canada (or New France) like the Spanish did in the Mexico area, they found profit in the trading for beaver pelts. So they also needed to be near waterways for a quicker return to France to sell the goods they collected in the America’s.