In French
Janvier (
January) is used as a name with feminine form Janvière. It is not a case of the month being used as a name. It is the French form of the Latin
Januarius.
In my native Poland
January (yah-nuh-AH-rih) is a masculine name but is not associated with the month as we call the month styczeń. Feminine form is Januaria which is also used in other languages.