The flag is described in Act on Finnish flag (380/1978) [1] and thus falls under
This file is in the public domain because it is a part of a decision or a statement by an authority or a public body of Finland. The Finnish copyright law of 2005 specifies that no copyright exists in such material (§ 9).
If, however, drawing the flag entails a creative work,
I, the copyright holder of this work, hereby release it into the public domain. This applies worldwide.
In case this is not legally possible: I grant anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law.
This image shows a flag, a coat of arms, a seal or some other official insignia. The use of such symbols is restricted in many countries. These restrictions are independent of the copyright status.