The Front National is the prime example of anti-systemic and populist party in France. But in the 2000s, La France Insoumise on the far left also developed a rhetoric that could fall into this category yet without sharing the ideology of far-right party. Reinvestigating previous studies, we may ask if the populist concept make sense to understand populism in France? Thus following a systemic field analysis, we study variations in the discourse of these two parties during campaigning and routine periods by analyzing the Facebook posts of their two leaders. They do not use the same strategies and, variations between the two periods highlight two different uses of populist rhetoric in addition to their two opposed ideologies. This paper discusses the relevance of the notion by stressing the need to think about populism within a systemic approach in the French political field that partly explains its spread to almost all parties.