Quote Originally Posted by Sascha Willems
Best way would be to do it like the german version of Call of Duty. They don't totally ruin the setting like Wolfenstein did and replaced the nazi flag with a flag with the same color but using a stylized iron cross instead of the swastika.
The stylised iron cross has been used in wargaming for decades, before personal computers, on board games. It's the simplest solution to the problem.