This looks much like any other common fly and can be easily confused with them. Confirming their identification may need some time online or with books. Wiki puts it this way. Dexia rustica can reach a body length of 8.4–12.7 millimetres (0.33–0.50 in) and a wingspan of 16–24 mm. These small tachinids have generally a black thorax, with grayish yellow pruinosity. Four longitudinal black vittae appear on dorsum. Abdomen appears greyish-brown or reddish, with a darker longitudinal dorsal marking, more or less evident. It is cylindric-conic, with two setae among each segment. Probocis is short and membranous. Females usually are darker than males.Wings are hyaline, with a reddish yellow tegula and a dark brown basicosta. Legs are reddish yellow.
And adds Adults can be found from June to August, feeding on nectar and pollen, which is when we found this example.
WIKIPEDIA : https://en.wikipedia.org/wiki/Dexia_rustica