Eurasian Tree Sparrows look similar to House Sparrows.
If you want to tell them apart, remember that Eurasian Tree Sparrows have a brown cap and House Sparrows have a grey cap.
Male and female House Sparrows look different while male and female Eurasian Tree Sparrows look similar.
In Europe you may find this bird in wooded open countryside, while the House Sparrow breeds in the more urban areas.

1st photo: Bird banding site, Naarden, The Netherlands, 1 August 2010
2nd photo: Korendijkse Slikken, Goudswaard, The Netherlands, 7 October 2009