This song and the scenes of the video are from the movie "Les Choses de la vie" by Claude Sautet. We see the beautiful Romy Schneider (how can one be so beautiful!) and Michel Piccoli, a marvelous French actor, one of the best.
The words of the song are these:
Tonight is September
and I've locked my room
The sun will never shine in
You no longer love me
Up there a bird flies by like a dedication
In the sky
I loved you so much Hélène
We must part
The planes will leave without us
I don't know how to love you anymore Hélène
In the house I used to love when we lived
Like a child's drawing
You don't love me anymore
I watch the evening fall in the mirrors
It's my life
It's better this way Hélène
It was love without friendship
I'll have to change my memory
I'll never write to you again Hélène
The story is no longer worth following
and I closed the book
The sun won't shine in
You no longer love me
It is a sad song but very beautiful, as is the movie, really. One of the best of Claude Sautet.