The IUPAC recommendations on this matter have been changed. Compounds such as $\ce{R{-}NH{-}Cl}$, $\ce{R{-}NH{-}NO}$, and $\ce{R{-}NH{-}NO2}$ are now named as derivatives of amides (see P-67.1.2.6).
The current version of Nomenclature of Organic Chemistry – IUPAC Recommendations and Preferred Names 2013 (Blue Book) reads as follows:
P-62.4 N-SUBSTITUTION OF AMINES AND IMINES BY HETEROATOMS
Traditionally, substitution on the nitrogen atom of amines and imines was allowed for all characteristic groups cited as prefixes (see Table 5.1). This approach is maintained in these recommendations, unless a higher class is formed that must be named in accordance with the seniority of classes (see P-41).
This new rule is applied to prefixes such as Cl and other halogen atoms, $\ce{{-}BrO}$ and other acyl similar groups, $\ce{{-}NO}$, $\ce{{-}NO2}$, $\ce{{-}OR}$, $\ce{{-}SO2{-}R}$, $\ce{{-}SO{-}R}$, and even $\ce{{-}OH}$ groups and
chalcogen analogues.
Thus, the preferred name for the compound that is given in the question is N-fluoro-N-methylhypofluorous amide and not N,N-difluoromethanamine.
A similar example given in the Blue Book is $\ce{CH3{-}N{-}(NO2)2}$, which is named N-methyl-N-nitronitramide and not N,N-dinitromethanamine.