Louis Larsonneur founded Substance in 2018 in the Oberkampf area of Paris's 11th arrondissement after working at Broken Biscuits and other specialty cafes in the city. The name is a statement of intent: substance over style, quality over trends. Louis roasts on site in small batches using a light Nordic approach, keeping 8 to 12 coffees available at any time, primarily single origins sourced through direct relationships from Ethiopia, Kenya, Colombia, Guatemala, Costa Rica, and Panama, with a particular interest in experimental processing and rare varieties. The space doubles as a wine bar in the evenings with a natural wine program, and a weekend brunch draws crowds to a menu of sourdough sandwiches, salads, and vegan options alongside the filter and espresso programs. Community is central: Substance hosts coffee workshops, producer talks, guest roaster pop ups, and regular collaborations with visiting roasters. Featured on European Coffee Trip and in Paris specialty guides, it has become a hub for the city's progressive coffee community.