Antonio Sciarretta's Toponymy
Before the Roman conquest, the region was inhabited by many tribes and confederations. In later province of Alpes Maritimae, those of the Vediantii (ancient diocese of Nice), Nerusii (ancient diocese of Vence), Sentii (ancient diocese of Senez), an unknown people of the Maritime Alps (ancient diocese of Glandèves), Bodiontici (ancient diocese of Digne), and Caturiges (ancient diocese of Embrun). In later province of Alpes Cottiae, that of the Ceutrones, Medulli, Segusini (ancient dioceses of Saint-Jean-de-Maurienne, Moûtiers-Tarantaise, and Susa). In later Narbonensis II, those of Deciates (ancient diocese of Antibes, later Grasse), Oxybii (ancient diocese of Fréjus), Albici (Vulgientes etc.) (ancient diocese of Apt), Salyes (ancient diocese of Aix-en-Provence), Reii (ancient diocese of Riez), Sogiontii (ancient diocese of Sisteron), and Avantici (ancient diocese of Gap). In later Viennensis, those of the Comani (ancient dioceses of Toulon and Marseille), Anatilii (ancient diocese of Arles), Desuviates and Cavares (ancient dioceses of Avignon, Orange, and Cavaillon), Tricastini (ancient diocese of Saint-Paul-Trois-Châteaux), Memini (ancient diocese of Carpentras), Vocontii (ancient dioceses of Vaison and Die), Segovellauni (ancient diocese of Valence), Allobroges (ancient dioceses of Vienne, Génève later Annecy, Grenoble, and Belley), and Helvii (ancient diocese of Viviers). In later Narbonensis I, those of the Volcae Arecomici (ancient dioceses of Agde, Nîmes with Alès, Maguelonne later Montpellier, Bèziers, Lodève, and Uzès), Volcae Tectosagi (ancient dioceses of Toulouse with Saint-Paopul, Lombez, Pamiers, Rieux, Lavaur and Mirepoix, Carcassonne, Narbonne with Alet and Saint-Pons-de-Thomières), and Sardones (ancient diocese of Elne later Perpignan).
Common remarks: the place-names have been put in the nominative case, an asterisk * means not attested, reconstructed form. The late place-names of probable Latin origin have not been included. The IE roots are in the form given by Pokorny's Indogermanische Wörterbuch. The links will be active when the single pages will be published, see the main page. For any comment, suggestion, email me.
Other strata are more difficult to identifiy. There is some evidence of a non-negligible A-language stratum in the coastal south of the region. Apart from this vocalism (and the presence of p- which contrast to known Celtic languages), no other particular shifts seemingly characterize this stratum. We might be tempted to attribute these toponyms, often hydronyms, to the Alteuropaeisch ('old European') stratum first proposed by H. Krahe as a substrate to historically known Celtic, Germanic, etc. languages.
Given the territorial continuity to Liguria in Italy, where two distinct non-Gaulish strata were identified - a possibly Celtic but pre-Gaulish one and a Liguro-Sicanian one - some of the A-language toponyms could actually belong to one of these two strata, particularly the Liguro-Sicanian one that was surely an A-language.
Finally, near the borders of Spain, there is at least one clear example of a name explained by Basque language, which points at an Vasco-Iberian superstratum that partially displaced a previously A-language or Celtic domain.
Greek names are of course rather popular in the coastal areas colonized by Greeks in the 1st millennium BC.