Differences between ĉe and en
What's the difference between ĉe and en in interrogative phrases? Example: "Ĉu vi laboras en McDonalds?" and "Ĉu vi laboras ĉe McDonalds?" Are they the same?
En means inside a location. * Ĉe* means near a place, or at someone's home.
So the question is whether McDonalds is a place you can work in, or a "someone" in whose home you work at. You might also consider por.
Unless you're talking about a specific McDonalds, I personally wouldn't say en.