Get citizenship in other EU country like Belgium , Italy etc and renounce French citizenshipThere are not plenty, maybe not even two, but there is one such clear cut taxation by citizenship case when moving to a tax haven with no workaround. And that is French citizens moving to Monaco - they are still taxed as tax residents in France for life, even if they move to a third country first, and even if they also have citizenship of a third country beside the french citizenship.
There are exceptions, but I wouldnt call them workarounds:
-A French citizen who had been a resident for at least 5 years as of October 13th, 1962 when the Franco - Monegasque treaty took effect, and has retained residency in Monaco since then, would not pay tax to France, and would be a so called privileged French citizen.
-A French citizen who marries a privileged French citizen, a Monegasque citizen or a third party citizen would also not pay tax to France.
-A French citizen born in Monaco who has consistently lived in Monaco since birth does not pay tax to France.
-A French citizen who gets Monegasque citizenship will not pay tax in France as Monegasque citizenship takes precedence.