When we were in Paris 2 years ago, we tried to book Michael but our time was very limited and he already had clients for the days we were there. However, he graciously offered us the services of a friend and we could not have been more pleased. A terrific, efficient way to see Paris! Michael's friend was another American, professional opera singer, just did this to help out and boy, was it worth it! It's possible Michael is just so inundated with emails he can't possibly respond...I'm sure he doesn't have administrative help! I'd say keep trying.