French phone number: +33 or a leading 0, one non-zero digit, then four pairs of digits separated by optional spaces, dots or hyphens. Lookarounds replace \b so the + prefix anchors properly, and they guard the whole word rather than digits alone: otherwise ten digits in the middle of an API key get tokenised, cutting the key in two. This is the one departure from the library catalog. The +33 form only matches when the first digit follows immediately (+33639981234), not '+33 6 39...'.