This is not a Petunia. It is an Auricula Primrose (Primula auricula cv.), also known as a Bear's Ear Primrose.
The wild species with yellow flowers is native to the mountains of Europe, but numerous intricately detailed cultivars have been bred for both border and show. Many Auricula cultivars are noted for their central floral discs of white, cream, green, or grey. The powdery farina that often graces both their leaves and flowers is an other distinguishing feature.