Although Franklin's style was part of the Age of Reason, I would argue that his subject matter began to cross over into Romanticism. Stylistically, Franklin is scientific. He holds to the rhetoric of the patriot and politician in most of his writings, avoiding the superfluous detail and emotion that would become such a part of the Romantics' work.
However, Franklin spoke about improving human existence and expressing individuality. His thirteen virtues was an attempt to achieve the most perfect human form and behavior. This desire to improve oneself and to examine the human condition is very much a part of Romantic literature, and would be revisited again in the works of Thoereau and Emerson.