Telephone country code +33 (dialed as 00 33or 011 33 from many places) is France. Telephone area code +33 1 is Paris and the surrounding area.
(The plus sign means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but North America (USA, Canada, etc.) uses 011, Japan uses 010, Australia uses 0011, and many other countries use different prefixes.)
Leichtenstein is telephone country code +423.
where is telephone country code 1816
The country code and area code of Potsdam, Germany is 49, (0)331.
The country code and area code of Feni, Bangladesh is 880, (0)331.
That is not a country code.
Gibraltar is country code +350.
Moldova is country code +373.
Slovenia is country code +386.
Togo is country code +228.
Liberia is country code +231.
Angola is country code +244.
Mozambique is country code +258.