I moved to London from Paris in March 2021 while my wife and son are still in Paris. I was assuming that I am a UK resident for tax purposes till I came across "the definition of 'domicile fiscal' in French tax law is enshrined in Article 4B of the Code Général des Impôts (CGI)".
In particular www.french-property.com claims that
The 'foyer' is generally meant to refer to the place where the family resides, which permits the authorities to consider that someone who lives temporarily outside of France because of their work remains resident in France if it is the country where their family resides.
I should add that both I and my wife and Indian citizens.