From ICAO Doc 4444 PANS-ATM
Vertical separation minimum
The vertical separation minimum (VSM) shall be:
a) a nominal 300 m (1 000 ft) below FL 290 and a nominal 600 m (2 000 ft) at or above this level, except as provided for in b) below; and
b) within designated airspace, subject to a regional air navigation agreement: a nominal 300 m (1 000 ft) below
FL 410 or a higher level where so prescribed for use under specified conditions, and a nominal 600 m (2 000 ft)
at or above this level.
Note.— Guidance material relating to vertical separation is contained in the Manual on a 300 m (1 000 ft) Vertical
Separation Minimum Between FL 290 and FL 410 Inclusive (Doc 9574).