The fare bucket will be assigned for the entire outbound or inbound leg based on the first segment of the leg. The first segment is in F therefore the passenger will be charged a first class fare for the entire leg (to Dubai and onwards to the final destination) - check-in baggage allowance and lounge access privileges in Dubai will be based on that fare.

In case the passenger decides to take a flight out of Dubai that offers first class cabin, the fare amount will remain the same.

Basically it is not the best solution for the passenger to select a connecting flight where the first class cabin is not offered as in this case the passenger is paying a first class fare for a business class product.