Even though you don’t have carpet, vacuum EVERYTHING. Furniture, floors, baseboards, tiny cracks and crevices, everything. Anything washable goes in the washer and dryer with the highest heat possible. And make sure you let the owner know, so they can treat the dog. Fleas are no fun for the pooch, either.
ETA: I totally forgot to mention the “throw out the vacuum bag or thoroughly sanitize the canister” step. That’s important.