The following are all signs that have been seen in various parts of the continent. I imagine some were examples of "lost in translation".
On the grounds of a private school in South Africa: "No trespassing without permission"
On a poster in Ghana: "Are you an adult who cannot read? If so, we can help"
In a maternity ward in Tanzania: "No children allowed."
In a Malawi hotel: "It is forbidden to steal towels please. If you are not a person to do such a thing, please do not read this notice."
In a restaurant in Zambia: "Open seven days a week and weekends."
On a window of a Nigerian shop: "Why go elsewhere to be cheated when you can come here?"
In a hotel in Mozambique: "Visitors are expected to complain at the office between the hours of 9.00am and 11.00am daily"
On a river in the Democratic Republic of Congo: "Take note: when this sign is submerged, the river is impassable."
In a Zimbabwean restaurant: "Customers who find our waitresses rude ought to see the manager."
A sign seen on a hand dryer in a Lesotho public toilet: "Risk of electric shock - do not touch with wet hands."
In a Botswana jewellery shop: "Ears pierced while you wait."