Both parking lights at the front suddenly do not light up

The two parking lights in the front of my car suddenly do not light up anymore. It's a 2008 VW Passat B6 Variant.

Possible leads:

• Fault code: Electrical fault in circuit
• A multimeter shows that the sockets which fit the parking light do not receive any power - on both sides.

Already checked:

• The bulbs are okay
• The fuses are okay
• The parking lights in the back are okay
• All other lights are okay

Any advice? Is there anything else a layman could check before sending it to the garage?