Can anyone tell why I can't create the second filestream object?

Stream s1 = new FileStream("C:\\test.txt", FileMode.Open,
FileAccess.ReadWrite, FileShare.Read);

Stream s2 = new FileStream("C:\\test.txt", FileMode.Open,
FileAccess.Read, FileShare.Read);

FileShare.Read should make it possible just read the file after it is
already openend.

The IOException for the second stream is:
Message    "The process cannot access the file \"C:\\test.txt\" because it
is being used by another process."

Thanks in advance!