Lifetime casts are far better than posthumous works as there is a fair amount of variation.
It was not until 1952 that France passed a law limiting the number of sculpture editions to 12. In 1968, the law was amended to require the name of the foundry on the sculpture and the number of casts. It was rehashed again in 1982 to refine the numbering system; Arabic numbers 1 through 8 being reserved for casts intended for the market while the Roman numerals I to IV were used for the so-called artist's proofs, which regarding the Musée Rodin, are reserved for cultural institutions. In addition, the date of the cast must be inscribed on the bronze. Sculptures are described as reproductions after 12 casts and must be labelled as such, according to a 1981 law designed to combat fraud in art transactions.
Those regulations had no impact on existing works such as Rodin's «Eternal Spring», of which between 50 to 100 different casts in four different sizes have been produced in both lifetime and posthumous versions.
Before settling on the Alexis Rudier Foundry in 1902, Rodin worked with 27 different foundries at a time when the concept of limited sculptures editions did not exist.
Until the 1970s, Sotheby's nor Christie's made distinction in their catalogue descriptions between lifetime and posthumous casts. Since then, the situation has improved somewhat.
In 1991 the New York State legislature passed a new sculpture law that was tacked onto the existing Arts and Cultural Affaires law, with civil penalties of up to $ 5,000 for tampering with a foundry mark or for not providing fill disclosure of information at the time of sale regarding the date of a sculpture, as well as its dimensions, medium, number of casts made and whether it was a lifetime or posthumous cast. A dealer or an auction would have to disclose clearly in writing whether the cast was authorized by the artist or by others.