$530,000 is right for L1. I'm pretty sure $1,050,000 is right for L2 as well, but there's always a chance I wrote it down wrong when I started the upgrade. I won't be able to verify until the upgrade is complete (~20 hours).
By my calculations, the Arc De Triomphe also varied slightly from the standard 2*L1, 3.5*L1, 5.5*L1, etc. progression for building output.