they don't know this - they search for eg. Baltimore and if you have it as your listed travel it will show as if you are there, except for a very small text at the bottom of your profile pic say (date123-date123) They reach out because the website gives the impression that you are available in that location, at that time. To avoid this as it gets so annoying I only put the city I am going to a week or two in advance. If you want those cities always listed - maybe have some text indicating that you only travel to those places with advance notice? (not that clients bother to read anyway!)
yeah its annoying when you waste time on messages like 'hey do you ever come to Nebraska?' I keep a catalog of the cities and the profile name/number, and a week or two before I arrive I send a message 'hey, just letting you know I will be in town these dates, if you would like to schedule something, let me know'. I have made a lot of bookings this way.
I have done overnights on first meeting before, most have worked out however I much prefer to have met before first. Better for everyone.
I would suggest 2 hour booking, you may be jet lagged and the time difference can wreck havoc. You also will not really know the proficiency of English of the provider until you meet (assuming you don't speak French, big assumption I know)
Consider asking someone you have spent overnight with previously if they would consider to meet you in Paris.
SP