How to get to the ENSAE building

The ENSAE building is located on the Ecole Polytechnique campus in Paris-Saclay area. My office number is 4023 (4th floor).

Here you can find the maps and information provided by ENSAE.

By public transportation: 

Take RER B line to Massy-Palaiseau station.

(From Paris, take trains bound for [Massy-Palaiseau] or for [Saint Rémy-lès-Chevreuse]. Never take trains for [Robinson]!)

Then, take a bus either 91.06(B,C) or 91.10 (map of the bus stops).

Get off at "Polytechnique-Lozère" bus stop.

From the bus stop, our building is 4 mins' walk away.

    or,

Take RER B line to Lozère station.

Then, take the infamous 300-step stairs up to the campus (Google says 18mins) 

By car: 

From Paris, take A6 to South, then follow A10, then A126.

Here is the easiest way to the building (Google maps).

Once on campus, follow the sign "ENSAE".

Campus map:

Here. 

More info:

Here and here just in case.