Originally Posted by MSPeconomist

Just to clarify, only the domestic DL flights are FC. The rest are business class, which DL calls Business Elite, abbreviated as BE. Also, you do not get any additional miles when you upgrade, whether with miles or SWUs (or for free as an elite on domestic flights). You earn MQMs and redeemable miles based on the fare class you purchased.

Lourdes is hot and crowded in August. It might be crowded all the time. To me it was fascinating to see the huge numbers of people in wheelchairs and on stretchers, plus many ambulatory elderly, some of whom looked very old indeed.

Of course, the Parisians flee in August and the city is partly closed and partly filled with mostly foreign tourists.

Are you looking at prices for BE fares to CDG or M class? Deeply discounted BE, such as S class, is more likely to be available at times when business travel is (expected to be) low. I'm not aware of DL having seasonable variations in M fares or sales on them, although there can sometimes be good sales on BE.