param (
    [string]$directory1,
    [string]$directory2,
    [string]$extension
)

Write-Output $directory1 $directory2 $extension

foreach ($item in Get-ChildItem $directory1 -Include $extension -Recurse) {
    $foo = Get-ChildItem -Path $directory2 -Include $item.Name -Recurse
    if ($foo) {
        Write-Output "Match:  $($foo.Name)"
    }
    else {
        #echo "Did not find $item"
    }
}