[seszett]

The rights to the Eiffel Tower have never been sold to a private entity, but the private entity that designed the night lighting kept their rights on it (which is the default, if the city didn't specifically ask for the rights to be transferred in the contract).

I don't think that's a good situation, but it has nothing to do with selling rights to a private entity.

[cco]

I'm not sure I follow, to my understanding it is not legal to take professional photographs of the Eiffel tower at night, is that wrong?

[closeparen]

Yes, because copyright remains with the original lighting designer and was never transferred - to or from - the public.