The BIPM website contains copies of several memoranda of understanding between BIPM and other organisations, which indicate that there are two distinct pictorial symbols that represent BIPM: one called the "emblem" and one called the "seal".
The first of the two images presented by OP (the one with the three vertical lines and the sans serif text) has been registered as a trade mark in the US, Singapore, and Canada. The Singaporean registration record describes it as the "emblem". Hence, I deduce that the second image presented by OP (the circular one with the three classical humanoid figures) is the "seal".
The lexico.com thesaurus lists both "emblem" and "seal" as synonyms of "logo", so as far as the original question goes, take your pick.