Lots of questions! O_O
Why Sandrine as a name?
How old is she?
What does she look like?
Why is she fleeing from her problems instead of facing them?
What are these problems she is fleeing from?
Why does she decide to flee to another country/continent? Is it because it is far away from where she was?
Why in specific did she choose those locations and not other popular sites like Florence, Vienna, Paris, London?
Is Munich the last, and current, place she is visiting? Meaning... did she already visit the other places, or was Munich between visiting other places?
Why is this guy dressed in all grey versus all black/white/yellow?

Why does he confront her and not someone else? What makes her so special?
Why is she confused by what he says? Is she simply forgetting about something, or is this a part of something still to come?
Now that she says he was beautiful (handsome might have been a better term for a guy, but it still works I guess, lol), why was she scared of him in the first place if she thought this?
If she thinks he's too beautiful to be human, then what else is there other than being human? Angel? Demon?
Why would she assume that something other than humans exist? Has she encountered other beings? Is she just paranoid and delusional? Was there a past event that explains her belief in the existence of any intelligent beings other than human?
Are we talking about aliens?
Is she afraid of being abducted? Again, if it happened previously?
If she was afraid in the first place, why would she ever leave this "nice luxurious" hotel room?
Why a deep slumber and not just normal sleeping?
How do we know a day has actually passed? How do we know she is awake? Couldn't it still be night in reality and she is dreaming?
Why does she assume that this is hell? Why is hell cold instead of hot, if it really is hell?
Why would a model version of Munich be in hell?
Why would she be in hell?
Just a few questions relating to reasoning and logic, so you can eventually answer all of these questions through the story (I don't recommend you just answer them directly, obviously, but most of these should be answered before too much story takes place so that the reader isn't completely lost). A reader likes to know that everything has a reason and purpose for being the way it is, and for characters to act the way they do. Even unbelievable scenarios need to have believable reactions from characters and believable reasons for things that exist or happen in the story. =]