Welcome to FT!
You will have more options out of LAX than ONT. I tried a consolidator site which showed availability on a $577.90 Nov 2/Nov 16 for LAX-CDG-ATH-CDG-LAX. Considering I ended up paying over $700 for my September excursion to ATH I do not think $672 is shabby. Of course, partly I'm paying for nicer weather

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