There is no way to get fields defined in C# (ex. System.Int32.MaxValue).
On the other hand, It is able to get F# fields (like struct defined in F#, record) by FSharpEntity.FSharpFields.
There is also a way to use reflection, but it can not get the F# type name of field signature.
For example, option is compiled as FSharpOption by CompiledNameAttribute.