What is the Hukm if one sees girls in the street after made Wudu (going to Masjid)?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

Looking deliberately at a marriageable woman is forbidden. Allaah says (interpretation of meaning): {And tell the believing men to lower their gaze (from looking at forbidden things) and protect their private parts (from illegal sexual acts, etc.). That is purer for them. Verily Allaah is All-Aware of what they do.}[24:30]. Moreover, the Prophet said: "O Ali, do not follow one look after another look, as you will not be accountable for the first one but you will be accountable for the second one." [Abu Daawood, Ahmad, At-Tirmithi and others] However, this (looking) does not invalidate ablution unless there is a white, thin, sticky discharge caused by sexual stimulation in which case it invalidates ablution.

Allaah knows best.