That's not actually true from a legal perspective anyway. The church is in charge of maintaining furniture even in the buildings that are owned by the state. I

That's not actually true from a legal perspective anyway. The church is in charge of maintaining furniture even in the buildings that are owned by the state. It's also not true that the papacy has always won when they challenged law, as it did initially challenge the law of 1905 by refusing to create a legal entity registered in France at the time, refusing to declare masses (as public reunions). In exchange, the state kept property of all furniture and non-cultual church property (presbyteries, seminaries, etc) without any clause for use by the Church. Many have been sold since then, or used for various purposes. The Church eventually caved in in 1924 but that was too late to regain use of these buildings. For the particular topic of the redesign of this cathedral though, I don't see the general public really caring about it, I don't see the church pushing for this design in particular either (this is just one proposition by one team, among many others) and I don't see the state caring much either beyond general considerations to choose between the various design proposals.