From the Airbus Corporate Jetliner
Riding on its aerodynamically advanced wing, the Airbus Corporate Jetliner flies high for maximum comfort and fast for maximum efficiency: cruise is at 0.80 to 0.82 Mach number, and cruise altitude is up to 41,000 ft.
The a/c in question is the A319. If it can cruise at that alt, the max certified operating alt on both the A319 and A320 should be similar, well above FL391.