For further reference, here is a link to the French Wikipedia and a map showing the borders of the Aedui confederation. Red are the Aedui, pink their clients, brown their allies, and grey their major ennemies. The map and corresponding article usually refer to Caesar's Commentarii de Bello Gallico
The confederation seems to have included these tribes:
Aedui
Clients: Ambarri, Segusiavi, Mandubii
Confederates: Brannovici, Bellovaci, Bituriges, Senones, Parisii
They also seem to have been on friendly terms with their northern neighbours, the Lingones.
http://commons.wikimedia.org/wiki/File:Maps_of_Eduens_people-fr.svghttp://en.wikipedia.org/wiki/File:Map_Gallia_Tribes_Towns.pngThis should be of some use gameplay-wise, as it gives us enough reasons to grant them a good number of starting areas. The territories of these tribes encompass cities like Bibracte, Alesia, Avaricum, Lugdunum and Lutetia.