The phrase is ordinary French, translating literally to not dynamic at all, and its online appeal comes from using formal sounding criticism for trivial disappointments. Short French voice lines circulate widely on soundboards because they are easy to loop, quote and drop into edits without explanation. This one has settled into reaction use, especially for moments built up as lively or impressive that arrive with no pace, movement or excitement. Its humour depends on contrast, so it remains popular for anti climax edits, ironic reviews and deadpan commentary clips.