Unfortunately, I don't think we have a perfectly clear idea. I've read a couple books that touch on the battle, David Hanson's Culture and Carnage, Hugh Kennedy's The Great Arab Conquests; these books might be a little dated (and politically motivated), so maybe someone with better sources can correct me. If these sources aren't academic enough, hopefully a mod can let me know.Here's a great online article on the battle although it is debating the macro historical significance of the event, rather than focusing on the composition of the armies. And there is an episode of the In Our Time podcast focused on the battle.

Hanson and Kennedy give us a good contrast for where the truth might lie though. Hanson's book is not very good overall, in my opinion, but he does attempt to describe both the Franks and the Arabs. The Franks, he says, would have arrayed themselves in a shield wall with heavy armor, shields, spears and swords. Hanson uses The Fredegar Chronicles, Gregory of Tours and I believe the Mozarabic Chronicles as his sources. Hanson describes the battle as one between heavy infantry and light cavalry, with the Frankish lines turning back numerous charges by the Arabs and inflicting heavy casualties, with maybe 10,000 Franks and 20,000-30,000 Arabs and Berbers. If you haven't read his book, though, all this should come with a caveat. The entire thesis of his work is that Greek hoplite tactics have shaped the entire Western mode of warfare, and is he is heavily biased in how he describes these events and how he selects and interprets his sources.

Kennedy, along with Rosamund McKitterick - who you can hear on the podcast, believe that the numbers on both sides would have been much fewer; McKitterick postulates that there were a few thousand Muslims at the most. The Arabs, after all, were wrapping up a raiding expedition around Bordeoux; not launching a campaign. Earlier in his book, Kennedy describes the Arab forces as lightly armored, and reliant on swords, spears and light shields in battle. Interestingly, Kennedy writes that Arab Muslim soldiers fought more as a force of mounted infantry, who move rapidly across terrain but dismount for battle rather than trying to charge and rout the enemy.

Angus McBride's detailed colour illustrations appear in several of the "Men-at-Arms" series released by Osprey a military history book publisher.

Books in Osprey's ancient history series usually contain a mixture of archaeology (photographed museum pieces such as weapons, armour, paintings of battle scenes, sites of ruined fortifications, etc.), as well as basic summaries of events during the historical period in question.

The paintings show the artist's attempt to "recreate" the period for readers and to display what the "typical" warrior of this-or-that nationality may have looked like, what weapons and armour he may have possessed, etc. Although the pictures are labeled with each soldier's nationality and position (infantry, cavalry, archery, etc.), they usually don't identify the weapons and armour by specific name and type.

For that, you may wish to search for the below Osprey titles in Google Books where previews of the text may be available.

In the meantime, here are a few Google image searches relating to McBride's "Franks and Muslims" artwork to get you started:

The Age of Charlemagne - Angus McBride illus.

Carolingian Cavalrymen - Angus McBride illus.

Armies of the Caliphates - Angus McBride illus.

The Moors - Angus McBride illus.