Seems like there's no departure airport requirement any longer. I think I remember something like that in previous years. But at least the T&C are very clear below the code now in the email, and not behind a link on a page somewhere.
*Enter the discount code while making a booking. A minimum ticket amount of EUR 170 for 1 ticket for 1 person, excluding taxes, surcharges and SAF contribution is a requirement. Your code is valid until 1 month after your birthday on flights within 1 year. Read the Terms and Conditions below.
The discount code is valid until 12-5-2025 and cannot be combined with other offers. The discount code can only be used once by one customer for one online booking with a travel period of 12 months. The code can be entered online when completing payment. Read the terms and conditions below.
Terms and conditions for the birthday discount code
-The discount code is valid only for online bookings made on KLM or via the KLM app.
-Minimum ticket amount: EUR 170 for 1 ticket for 1 person, excluding taxes, surcharges and SAF contribution.
-Booking period: 1 month, from the date of the customer's birthday.
-Travel period: travel must be completed within 1 year, from the date of the customer's birthday.
-Valid in Economy, Premium Comfort and (World) Business Class.
-Valid on flights with a KLM flight number, operated by Air France, KLM, Delta Air Lines or KLM Cityhopper.
-Discount codes may not be used for multi-destination travel. The place of departure must be the same as the final destination.
-Offer applies to the first 400 discount vouchers used per code. Maximum 1 voucher per user.
-The discount applies to the entire booking and not per passenger.
-The discount cannot be used in combination with other offers or travel vouchers and does not apply to Flying Blue reward tickets.
-The discount code must be entered during booking and cannot be processed afterwards.
-In case of ticket cancellation, the discount amount will not be refunded.
Edit: The AF code is more restrictive:
*All persons born in April can benefit from a €50 discount on their next booking, valid until 11-05-2025. To do so, simply book a ticket online on airfrance and enter the code during the purchase process. Travel period from 11-04-2025 to 11-04-2026.
Conditions of use:
- Code limited to 200 discount coupons. Use limited to one coupon per user.
- Discount applicable to the entire booking file and not to the passenger.
- Usable only for immediate payment on our website with e-ticket issuing
- Valid only from: Spain
- Applicable classes of travel: Economy, Premium, Business
- Minimum ticket amount excluding airport taxes and surcharges (a discount will be applied for each individual booking reference) before application of the discount: €170
- Valid on flights operated by Air France, KLM, Delta, UX and KLM Cityhopper, only with AF or KL code.
- Payment method: Credit card
- Non-cumulative discount, does not apply to award tickets.
- Use of this code is subject to Air France's general terms and conditions of sale.