As the Germans occupied France, what was done to critical businesses / factories that also had military applications?

[axisinquirer]

Not sure if that title is too accurate.. I'll try to clarify

There were, obviously, many businesses or factories that were absolutely critical to normal life. For example, a business based in Paris that makes medical supplies and equipment. Of course, it would be absolutely critical to normal life in Paris. But it also would be very useful to the German military.

Are there any examples of this situation? Did the Germans completely take over these businesses to supply their own needs? Did they only take a percentage? What else?

Thank-you