Well, this does say that "some truffle oils are made with truffle residues". Now maybe this is rare in the US, but at least in France it's the only kind of oil

Well, this does say that "some truffle oils are made with truffle residues". Now maybe this is rare in the US, but at least in France it's the only kind of oil that is allowed to be called truffle oil (well, "huile à la truffe"). It could be called "olive oil with truffle taste" otherwise ("huile d'olive/tournesol/colza au goût truffe"). It's really not difficult to find here, and it is absolutely made with real truffle (the broken pieces that can't be sold as truffles). I don't have any at home because I don't care for it, but one I can find at my usual supermarket for example contains "TUBER AESTIVUM (1.1%)". This is known to be a so-so variety of truffle at best. The next-level product (at almost 40 €/L) specifically says that the truffle in its ingredients is "Périgord truffle (Tuber Melanosporum) 1%". This is probably a good enough truffle oil if you like that. Looking up the products here in Belgium though, it seems like only "truffle taste" oils are available in the regular supermarkets, but that is also clear from the product names ("Bereiding van Olijfolie van Eerste Persing 99,7% met Truffelsmaak").