Hadith: A slave belonging to some poor people cut off the ear of another slave belonging to some rich people, so the owners of the perpetrator came to the Prophet (may Allah's peace and blessings be upon him) and said: O Messenger of Allah, we are poor. The Prophet (may Allah's peace and blessings be upon him) did not stipulate any compensation to be paid by the perpetrator

عن عمران بن حصين أن غلامًا لأناس فقراء قطع أذُنَ غُلَامٍ لأناس أغنياء، فأتى أهله النبي صلى الله عليه وسلم ، فقالوا: يا رسول الله، إنا أناس فقراء. «فلم يجعل عليه شيئًا».
[صحيح] - [رواه أبو داود والنسائي وأحمد]

‘Imrān ibn Husayn narrated that a slave belonging to some poor people cut off the ear of another slave belonging to some rich people, so the owners of the perpetrator came to the Prophet (may Allah's peace and blessings be upon him) and said: "O Messenger of Allah, we are poor." The Prophet (may Allah's peace and blessings be upon him) did not stipulate any compensation to be paid by the perpetrator.
[Authentic hadith] - [An-Nasaa’i - Narrated by Abu Daoud - Narrated by Ahmad]

Explanation

The Hadīth relates that a slave or a small boy belonging to some poor people cut off the ear of his peer who belonged to rich people. The owners of the former went to the Prophet (may Allah's peace and blessings be upon him) and informed him of the fact that they were poor. The Prophet (may Allah's peace and blessings be upon him) did not stipulate any compensation for the owners of the victim. The reason for that was that the offender was young, and his action did not necessitate punishment. Some scholars stated that legal retribution was not carried out in this case because the offender was young. However, the blood money due on crimes less than murder still had to be paid by his male paternal relatives, who were poor. Therefore, the Prophet (may Allah's peace and blessings be upon him) absolved them from paying the indemnity. Moreover, an intentional crime by a young boy takes the ruling of crimes committed by mistake according to the consensus of the scholars. Therefore, blood money was not due on his male paternal relatives because they were poor; meanwhile, blood money is due on the male paternal relatives who are rich. The Prophet (may Allah's peace and blessings be upon him) probably paid the blood money from the public treasury.