Hi Olivier,
That was the on off/off switch in a Fw 190 G-3 for the 1-axis autopilot. See also the LIFE cockpit shot of G-3 W.Nr. 160016 I published in my blog about Luftwaffe control sticks
http://germancontrolsticks.blogspot....0-g-3.html?m=1
You can see the same switch. On the left cockpit console the Richtungsgeber switch to set the course marked R (Rechts) and L (Links) can be seen.
Your photo (by Jeff Ethell) was presumably taken in Italy where several G-3 were captured.
Best regards
Roger