You can go first to the library "Armes et Collections" Avenue de la République (Subway station : Parmentier). They probably give you some good model shops in Paris. You can, perhaps ask it on their website before.
In Le Bourget museum, you can also found a technical library with a lot of airplanes models. There is also a library in Invalides museum.
Only two days for this programm ! It'is to short . . . . . . . !
Shops are open on Saturday but not on Sunday in France. Museum's library are also open on Sunday.
I had a look at the "Armes et Collections" website, it seems to be a fantastic library!! You had a good idea to visit that library first! Is A&C in rue de Crussol, too? Is that another library (of A&C)?
Not very far from that library is Azimut Productions. Do you know this shop?
I did some internet search and found "Blast Models" in 5 rue Crozatier. This shop looks to be interesting, too? Perhaps, you know "Blast Models"?
Of course, two days is not a lot - but it's a beginning...
I only used to go to "Armes et Collections" and I don't built models . . . . . Blast Models is known as a good shop. Perhaps you can also ask questions on Forum : "Les colleurs de plastiques"
Armes et collection move to 8 rue de Crussol. Very close to the previous location but...
Both Azimut (rue de Turenne) and Blast (Rue Crozatier) are really great shops. Visit Euromaquette 88 rue de Charenton too (the owner is very sympathetic and helpfull)and Eol 3 rue du Louvres.
Also try EOL... They have a lot of choice of models (Plastic; wood, flying or not, whatever... They are now located not too far from le forum des Halles at 3 Rue du Louvre.
They have a website to wet your appetite : http://www.eol-model.fr/
Thank you very much for your suggestions! During my very short - but very nice! - stay in Paris I was able to visit the Musée de l'Air at Le Bourget and the Musée de l'Armée. Both museums present their WW I collections in a new and fine way, chapeau!
I visited different shops, too. The "Armes & Collections" library has got a big selection of useful books. Then I went to four model shops: "Azimut Productions" close to the A&C library (well assorted, mostly WW II, staff out), "Blast Models" (well assorted, WW II, staff seemed not to be interested in selling something...), "Euromaquettes" (friendly people, huge range of AFV, aircraft, ships, cars, figures and paints, attention: this shop moved in mid-February to a new location just south of Gare de Lyon, called the "Gamma Tower"!!) and "Quarter Kit shop". The owner of this shop runs "Gaso.line" and produces very fine WW I resin tanks in 1/48 scale: the German A7V, the British Mk IV Male and Female, the French Schneider, St. Chamond and the FT-17 in three different variants. The people in this shop were the friendliest of all the hobby shop people I met during my stay. Even their dog brought his tennis ball for playing.... I spent a happy time in this location with a lot of laughter and a cup of coffee offered by the shop owner's wife.
Once again, thank you very much for your useful suggestions! I have decided to visit Paris another time!
One museum that I always enjoy while in Paris the Naval Museum in le Trocadero. This is a wonderful place. They might be poor on WWI items but they do have a huge collection which is quite fascinating for lovers of history.