If you read french or want to dive in the mostly english code, you can fork https://github.com/betagouv/mon-entreprise https://github.com/betagouv/mon-entrepris

If you read french or want to dive in the mostly english code, you can fork https://github.com/betagouv/mon-entreprise https://github.com/betagouv/mon-entreprise. It doesn't fill tax forms, but it's a set of simulations and a framework to write more models and generate UIs automatically.