Paris to Bern then use the Berner Oberland Regional Pass?

It would help to have some more detail on your time in Switzerland. Basel to Bern. Any time spent in Basel or Bern? How long in Lauterbrunnen/Murren/Grindelwald and what are your plans while there? Where to after?

No, no time spent in Basil or Bern. Literally just taking train to Lauterbrunnen. Should I use a Swiss Travel Pass OR use a Berner Oberland Regional Pass when I get to Basil since it's included in that pass.

I would definitely recommend a pass as they are super convenient. As for which one, that depends on what your plans are.

You can see what’s covered with the Regional-Pass Bernese Oberland here:

https://www.myswissalps.com/regionalpassberneseoberland/validity

And what’s covered with the Swiss Travel Pass here:

https://www.myswissalps.com/swisstravelpass/validity

I’d check the number of days you would use the pass, the price of the passes and which one covers more of what you plan to do.

You can compare the prices here:

https://www.regionalpass-berneroberland.ch/en/prices-tickets/

https://www.sbb.ch/en/leisure-holidays/inspiration/international-guests/swiss-travel-pass.html

They are pretty close, but the Swiss Pass is slightly more expensive. However, if you have a child traveling with you, you can get a Family Card that allows free travel for the child with your adult Swiss Pass for free. A child BO. Pass, which allows free travel, costs 30 CHF per child.

The coverage of the passes is slightly different, mainly with respect to which mountain lifts are fully covered, and which get a discount.

And the Swiss Pass covers all of Switzerland, while the B-O Pass only covers that region. This can make a difference for your travel to and from the B-O—-you will have to add the cost of travel from Basel to Bern (40 CHF), and from Bern or Luzern to the airport or Swiss border, to the total cost if using the B-O pass.