Does Paris runs or just the CBTC capable of running? You need more than CBTC to run at 85 second headway. Loading/unloading time became huge problem at that interval.

I just checked Line 14 schedule and the most I can find is 34 train per hour, which is approx 105 second headway.

I am not saying that CBTC isn't capable of running higher interval than regular ATS and wayside signal (which is actually a very old technology), but in most case it doesn't matter. Even without moving block of CBTC, a very short static block (say, 100m) and in-cap signally should theoretically have the came capacity as CBTC.