2008/9/4 Florence Devouard Anthere9@yahoo.com:
The definition of a "mécène" is not so different from the definition of a sponsor, though the French article hints that the "mecène" does that for philanthropic reasons, whilst the sponsor does that for commercial reasons.
The traditional distinction would be "patron" - you would talk about so-and-so being the patron of an artist, of Michaelangelo working under the patronage of the Pope. The patron would gain advantages, usually prestige, and the artist would gain a living and perhaps respectability.
But this is a bit archaic - it would seem very strange to use it in a modern context.
Generally speaking, I'd say "donor" implies it's a simple gift, whilst "sponsor" suggests they explicitly intend to capitalise on it.