Complex sentence: A joint venture of Ford and Mathis was created under the name of "S.A. Française Matford" which copied the style of contemporary British Ford models and soon became one of the biggest competitors of Mathis.
Split into simpler sentences: A joint venture of Ford and Mathis was created under the name of "S.A. Française Matford". Matford, which copied the style of contemporary British Ford models, soon became one of the biggest competitors of Mathis.