Pycharm and sys.argv arguments

In PyCharm the parameters are added in the Script Parameters as you did but, they are enclosed in double quotes "" and without specifying the Interpreter flags like -s. Those flags are specified in the Interpreter options box.

Script Parameters box contents:

"file1.txt" "file2.txt"

Interpeter flags:

-s

Or, visually:

Then, with a simple test file to evaluate:

if __name__ == "__main__":
    import sys
    print(sys.argv)

We get the parameters we provided (with sys.argv[0] holding the script name of course):

['/Path/to/current/folder/test.py', 'file1.txt', 'file2.txt']