Linked visits are alternatives or continuations, not a claim that all are adjacent.
What to look for on site
The visit has two levels, from the lower to the upper chapel. Look at the architecture before concentrating on the windows. Entry is within a judicial complex with security checks.
How should I prepare to see Sainte-Chapelle's stained glass?
Allow time to study the stained glass rather than taking just one photograph of the nave. Light and crowd levels change the experience. Include security checks and your booked time slot in the visit plan. These are separate from Notre-Dame's arrangements.
Are the duration and budget guaranteed?
The suggested duration of 1 h 30 is planning guidance, excluding travel and unpredictable waiting. Budget categories are editorial indications, not ticket prices. Free entry can have exceptions for exhibitions and activities; confirm the exact visit with the provider.
Sources may use French. Confirm opening hours, ticket inclusions, reservations and temporary restrictions for your exact date. For accessibility, check the entire journey from transport to entrance and facilities with the provider.