I want to set up a Flickr page for an institute, but if want to fill in the sign up form I have to fill in birthdate, gender, surname and so on. Should I fill in fake data or is there a smoother way?
I think you can create a Flickr with a google account.
That's what I did and I don't remember having to fill these informations. (apparently not)
After reading the terms of service
You can use Flickr for non profit, but it seems to be tolerated more than encouraged.
In any case you must be register as an individual.
Maybe using the company owner, or director identity is a valid alternative to entering your own details (if approval is given).
And since you can control the visibility of the informations in your profile it's not such a big deal to enter personal details.
Change the visibility of personal details to "friends and family" to hide them.
I would't recommend flickr for a commercial activity as they can close down the account for that reason.