Transit visa question in Schengen is a very common and frequently asked question here. The answer lies here.

I am referring to the official European union [Schengen, Borders & Visas/Visa policy](https://ec.europa.eu/home-affairs/schengen-borders-and-visa/schengen-visa_en) publication, which is precise and clear.

> **I have connecting flights, with a stop at a Schengen state airport. Do I have to apply for an airport transit visa or a short stay visa?**
> 
> It is important to distinguish between two situations:
> 
> 1. transit through the international transit area of an airport (onward journey where you do not leave the international transit area of the airport)
> 2. transit via the territory of a Member State albeit limited to an airport (onward journey where you leave the international transit area of the airport).
> 
> An airport transit visa (ATV) authorises you to pass through the
> international transit zone at an airport located on the territory of
> the Schengen State and to await a connecting flight to a non-Schengen
> country. The ATV does not allow you to enter the Schengen territory
> (to stay at a hotel or to take an onwards flight to another Schengen
> State, for example). To find out whether you need an airport transit
> visa, you can consult the overview on our website, click here.
> 
> Traveling to a Schengen State via another Schengen State airport is
> not considered an airport transit neither is travelling to a
> non-Schengen country via two Schengen state airports. All flights
> between two or more Schengen States are considered to be «domestic»
> flights. Depending on your nationality, you might need a short stay
> visa as you enter the Schengen area – even if the stay only lasts a
> few hours and you remain in the airport (outside the international
> transit zone).

[List of third countries whose nationals are required to be in possession of an airport transit visa when passing through the international transit area of  airports situated on the territory of one/some Member States (November 2022)](https://home-affairs.ec.europa.eu/system/files/2022-11/Annex%207B_en.pdf)

> **Can I enter the Schengen area in country X, while the visa was issued by Schengen country Y?**
> 
> As a general rule you may cross any Schengen border with visa issued
> by any Schengen country. However, the short-stay visa does not
> automatically entitle you to enter the Schengen area. See FAQ no 16 on
> checks at the external borders.