Pick the spine
Impressionists → Orsay; Latin lanes → Pantheon + one hall. Do not force both. After lunch walk Saint-Germain; afternoon chairs in Luxembourg.
Guide · independent travel
Left Bank day: Orsay or Pantheon, Saint-Germain transit, Luxembourg close. Tower tickets another day.
Left Bank day
Impressionists → Orsay; Latin lanes → Pantheon + one hall. Do not force both. After lunch walk Saint-Germain; afternoon chairs in Luxembourg.