Indeed these are the first stamps of Lebanon and Syria under the french occupation, the first set used French stamps and is very rare as only a small quantity was overprinted, the 2m is very rare. The overprint was done by Gedeon Printers, Beirut
This cover is very valuable as it contains the first 4 stamps nicely used in Beirut Lebanon. These stamps can not be purchased without a competent certificate.
The next stamp is from the same set, a 9pi, used in Beirut (Arabic Beirut can be seen on lower right).
After the defeat of the Ottoman Empire in World War I, Lebanon was occupied by French Forces who considered this country as an enemy: TEO: Territoires Ennemis Occupes.
Then we used Levant stamps for Lebanon and Syria, they are not rare except the high value 100pi