Here are the installation directories:
Standalone : /Applications/Arturia <product name>/
VST : /Library/Audio/Plug-Ins/VST/<product name>.vst
AU : /Library/Audio/Plug-Ins/Components/<product name>.component
RTAS : /Library/Application Support/Digidesign/Plug-Ins/<product name>.dpm
Sounds and Prefs : /Library/Preferences/<more or less product name>/
You may clear & destroy'em for complete uninstall.
Moreover, this is always a good idea to fully uninstall a demo before installing a full version (not the case here, but generally worth).