Why? I know you do know the answer. Because every planner of infrastructure or services in France worth its salt spends a lot of time in making things comlicated. By design. And when then some super smarts like us here on the board have figured it out, there is still room left for random anarchy ensured by poor execution: by signs actually saying the wrong thing because someone didn't pay attention when putting them up. Or by clueless staff who contradict what the website says which contradict what the signs say which contradict what another staff says. Or by strikes that nobody konws about.

Same things at CDG: what is the logic of having Terminal F with concourses F1 and F2, where you'd then expect gate numbers to start with F1x or F1xx and F2x and F2xx respectively - mais non. Gate numbers in F1 start with F2x, and gate numbers in F2 start with F4x I think.

By analogy to F1 and F2 you would then expect that 2E with three concourses would also just be concourses E1, E2, E2. But no. In 2E, concourses have letters. And those letters have nothing to do with E, but they are K, L, M. And to have laughs every day, the ADP guys made sure to mix contradicting with confusing information. For instance, when you get to 2G and want to transfer to 2E, there are places where there are signs to "Terminal 2E", other places where there are signs to "K, L, M" (without the word "gate" - adding to the confusion as some people might have ended up thinking that following these signs would lead to the place where KLM flights leave from).

But as mentioned earlier, whilst ADP and Air France struggle with too many bureaucratic farts with a messy minds, they are topped by SNCF. If you believe that Orly gate and terminal numbering don't make sense, come to Gare de Lyon. Every railway station in the civilized workd that I know (which does exclude quite many I guess, but still) has some logic sequence in its track numbering or labeling. Most use numbers, as letters are used for parts of the actual platform so that people can locate their carriage. When the layout of the station is a little complicated, they try to make track numbering easy. Example, Berlin Central station (and here we are talking about a city so disorganised they don't even know whether they should fix or re-build a messed-up airport project). Berlin Central Station has two levels, upper level is going East-West, lower level North-South. Lower level has lower numbers, platforms 1-8. Upper level has higher numbers 11-16.

Now take Paris Gare de Lyon: they have two halls, hall 1 and hall 2. Makes sense so far. But instead of having hall 1 with tracks 1-12 and hall 2 with tracks 20-29 there was a strike of genius: Hall 1 has tracks with letters, Hall 2 has tracks with numbers. And letters don't go A, B, C, D, E, etc. Non Monsieur, that would be too obvious. They go A, C, D, E, G, H, I, J, K, L, M, N. Why there are gaps between some letters (A>C, missing B) but not others (D>E) is a bureaucrat's mystery. Hall 2 on the other hand at least is consistent in its lack of logic. They start at 9 - don't ask why not at 1, that's another bureaucrat's secret - and then go 11, 13, 15, and so on. But hey, this is still too obvious. So what they have done to really make things messy: when you stand in front of the trains in Hall 1, the lower platforms (A) are on the left, the higher (N) on the right. In Hall 2, it's the opposite.

Seriously, not even Kafka could have come up with that.

And I am sure they have 10 people at Gare de Lyon on a CDI (permanent job) playing Platform Scrabble. Sure, at least 2 are always sick on any given day (=not productive either), 2 are taking their RTT (=don't work), 1 is on permanent strike (=doesn't work), 1 is on a training course (=1 doesn't work), 1 is seconded to a project to SNCF headquarters to take part in the complexification of the fare structure (=no work either), and 2 are full time union representatives complaining about "un manque d'effectifs et une dégradation des conditions de travail". But that doesn't matter, because in any case those ten people would only be executing orders of the "Centre de vérification des instructions, cellule Paris-Sud Est", which employs 15 people just for platform numbering, who report into the Greater Paris control centre, which in turn takes its direction from a steering committee of 30 people from SNCF National HQ, the Ile de France region, the Ministry of Transportation, the Paris City Hall, the Association Française des Rivérains des Gares, and some trade unions. And because they cannot decide over a 7 year period, the decision is taken elsewhere, "arbitrage à Matignon", but only when it's more than 2 years before the next election.

Compared to that, Orly is paradise and ADP a lean, well-run company. It still should be privatized.