Offer architect house 150sqm / 750 thousand €

Getting better and better. ^^

Do you have any plans that you could post here?

But actually, it doesn't really matter, I can't quickly imagine any static (or other) scenario that would justify the price.

Unless the house is hung from below on a bridge...

What argumentation did the architects use to present the offer? How high is their fee?

Shoot the architect to the moon. Someone wants to profit from you. The equipment should also be possible for half or at least easily 350k€. He would never set foot in my home again.

...Architectural services level 3 to 4 completely included!

What does that mean? What are the levels?
Do you have a cost breakdown or only the total?
The only chunk mentioned in your project description above is the Bauhaus style. You can understand that as a cube with a flat roof as the basic form, but also much more. We recently discussed the topic here, where authentic interior doors were supposed to cost €2,000 each...

I don't know how the construction prices are in the Freiburg area. We are building in the greater Stuttgart area, also with architect Lph 1-5.

Bauhaus style with flat roof. 210 sqm pure living area, 55 sqm double garage, partial basement with 70 sqm including 20 sqm hobby room as well as large covered terrace. 1 master bathroom, 1 children's bathroom and guest WC including shower. All showers are level with the floor. Air-to-water heat pump, underfloor heating, plastic/aluminum windows, parquet, large tiles.

We end up all-in, except garden, so also connections etc., significantly below you. But we also do quite a bit ourselves.

Wow, we are not building with an architect, but 180 sqm plus basement with ventilation system and come out at about half the cost. Well, okay, it’s not in Freiburg and is a city villa. Maybe he wants to earn a golden nose or that you go somewhere else.

...Architectural service level 3 to 4 completely included!

It means he only supports you up to the building permit. For that amount, you can hire 2 more architects who cover all modules.