The entirety of France, including its southern coast, is north of Boston.

Acktyually, the southernmost point in France is 50°01′ South (Îles de Boynes in the southern Indian Ocean). 🤓

Somewhat more legitimately, there are also inhabited French lands further south than Boston: Corsica, French Guiana, French Polynesia, Réunion, etc. Corsica even counts as "Metropolitan France" (as opposed to "Overseas France") while still -- barely -- beating Boston by about 1°.