Entering France on student visa from USS

[catfrance90]

Hi,

I'm from the US and I'm coming to France to get a masters degree in September. I am planning to leave in late June and stay with my partner in Switzerland on a tourist visa for the summer. The OFII long stay visa says the following:

“If you are transiting through another Schengen state, the stamp must be
obtained from the relevant authorities in the country of transit. In this
case it is understood that you will enter France no later than five days
after this date of entry.”
Does this mean I need to leave the Shengen zone and re-enter for my French tourist visa to be valid? And can I go to the UK, or do I have to come back to the USA and then fly directly to France?