import re
line = r'#pragma MESSAGE "Hello World" 0000=1 /* Clarification 0001: [[Specific Clarification]] */'
content_new = re.sub(r'/\*[^*]*\*+(?:[^/*][^*]*\*+)*/', lambda x: re.sub(r'.*(\[\[.*?]]).*', r'# \1', x.group()), line)
print(content_new)