Marco,
It is certainly an Eucalyptus, but I cannot say for sure what species.
Sometimes it is hard to identify this tree without other clues. Bark, colour and size of flower, height etc. Even the gum nuts are difficult to put into aspect (size) just from one photo.
Also there are now hybrids which may be grafted plants.
Can you say "where" you found it, I mean is it growing in a garden or park? Did you have any other photos?

I found in an uncultivated field but it was definitely planted.
Send more pictures. The bark seems to me particularly.
One person told me it should be:
ROBUSTA PYTOCARPA MAHOGANEY GIGANTEUM AWHAIN
but it seems wrong. It 'a collection of botanical names meaningless.
Send more pictures.
Thank you!
mark

Other photo.
Height 4 m, trunk diameter of 15 cm.
thanks
Marco