Two-year-old Saurav Ghai was walking along Southampton Road in Gospel Oak with his childminder on 18 January 2007 when the incident happened.
During the Health & Safety Executive (HSE) prosecution, Southwark Crown Court heard how the pair were walking in high winds when a section of the boundary wall from the Wendling Estate collapsed, falling onto them.
They were taken to the Royal Free hospital, but Saurav died shortly after. His childminder suffered injuries.
Camden Council pleaded guilty at an earlier hearing after being charged with breaching section 3(1) of the Health and Safety at Work etc Act 1974. It is responsible for maintaining the wall that collapsed.
After the sentencing, the child's father Mr Vinay Ghai said: "We are grateful to the HSE for their efforts and persistence when dealing with the council, for keeping us involved at different stages of the investigation and being understanding of our frustration at many times during this period. Without HSE's involvement we would never have found out the proper facts that led to Saurav's death.
"It has been four years since our son was killed and we hope his short life will at the very least highlight the importance of the care required to make our public places safer."
HSE Inspector Michael La Rose said: "Saurav should have been able to walk down the street without his life being put at risk, tragically this wasn't the case.
"His parents are now facing life without their son because this council simply failed to maintain a wall which was in a poor condition.
"This tragic incident should serve as a reminder to all organisations to keep their building stock safe, including boundary walls."