So as I understand you want to live in a french speaking area and commute to Zurich daily. If so, you will need to be up for a long commute. I think the closest acutally would be living in France just outside Basel, but then you'd have to deal with being non-resident in Swiss, crossing border, with all the associated permit hassles.

If communting from Biel/Bienne, even by the most direct train it is 1h10m, which is only from the main stations, including travel to/from the station in Biel and Zuerich adds to this even more. So it will be well over your 70 min. maximum. Finding a house in outerlying Biel/Bienne in french speaking area is all to the west, ie. even further from Zurich, so add some more commuting time.

I guess it is up to what compromises you are willing/not-willing to make. I think you will have to decide to live in a german speaking area, or have a very long commute more like 1h30m or more, or perhaps live in the center of Biel/Bienne with close proximity to transport on both ends.