Paris Charles de Gaulle and Orly, along with other major French airports, handle pet arrivals routinely, and France's flag carrier Air France is a reasonable benchmark for what to expect. Small pets can travel in the cabin up to roughly 8kg including the carrier, in a soft-sided bag around 46 x 28 x 24cm that fits under the seat in front — but airlines typically allow only a handful of cabin pets per flight, often as few as four to six, so book your pet's spot when you book your own ticket.
Larger pets travel in the hold, subject to the airline's own breed and temperature restrictions. Brachycephalic (flat-faced) breeds — bulldogs, pugs and similar — are commonly excluded from hold travel altogether on safety grounds, a restriction worth checking if that describes your dog, since it isn't a universal EU rule but an airline-specific one that several major carriers, including Air France, apply.
As with much of Europe, hold travel for pets is often suspended during summer heat, since extended time on a hot tarmac is a genuine welfare risk. If your pet is too large for the cabin and you're travelling in July or August, check the airline's current seasonal restrictions before booking rather than after.