It's hard to be certain what's going wrong, because the example code is incomplete, and so cannot work at all as it stands.
However, assuming the real code you are running is more or less sane/complete, your problem is probably caused by not adding the directory itself to the list of paths.
A basic script should look something like this:
import sys
from PyQt4 import QtCore
def directory_changed(path):
print('Directory Changed: %s' % path)
def file_changed(path):
print('File Changed: %s' % path)
app = QtCore.QCoreApplication(sys.argv)
paths = [
'/path/to',
'/path/to/files_1',
'/path/to/files_2',
'/path/to/files_3',
]
fs_watcher = QtCore.QFileSystemWatcher(paths)
fs_watcher.directoryChanged.connect(directory_changed)
fs_watcher.fileChanged.connect(file_changed)
sys.exit(app.exec_())