Powershell question PnP get File

Hi got a question regarding variable in the PnP get file command

When putting the values in hardcoded it works 

But when using a variable it fails on the filename

Get-PnPFile -Url $UrlToFile  -Path $DownloadFilePath -FileName $Filename -AsFile

in both situations the input is exact the same only difference hard coded or variable.

Does anybody have a idea what is going wrong?

thanks in advance

Paul