The new-look factory is part of an integrated campaign created by Ford Europe PR and branded content agency Cake in the build-up to the launch in October.
Residents and workers at the Ford Niehl factory were dazzled to see the previously grey plant transformed by a blue, red and yellow coloured 3000-metre wrap around the building.
The "Fiesta love factory" is part of an integrated campaign, which includes a series of virals illustrating the theme "Ford Fiesta created with love".
A spokeswoman for Cake said: "It's all part of the mythology behind the Ford Fiesta Love Factory. It's a pan-European campaign and the natural place to start was the main production centre in Cologne."
"It has been rewarding to see it unveiled at last. There were a lot of logistics behind it, including getting permission from the local council and having the bespoke wrap especially made in the UK and transported to Cologne."
More than 12m Fiestas have been sold since the car's introduction in 1976.