The historic district of Vieux-Longueuil centres on Rue Saint-Charles, the old main street that runs parallel to the river a few blocks inland. It has survived the suburban development that overtook much of the city and retains a row of late-19th and early-20th-century commercial buildings, now occupied by cafes, restaurants, and independent shops.
The neighbourhood has a low-key but genuine quality: it is where Longueuil residents actually eat and drink, rather than a tourist precinct. The pace is slower than Montréal, prices are significantly lower, and you are likely to hear almost entirely Québécois French. Saint-Antoine de Padoue Cathedral, a large stone church that has anchored the neighbourhood since 1811, is at the north end of the street and worth a look for its interior.