The 307s makes use of a reworked 306 platform, that can also be found on the Citroën Xsara as well as the 1991 Citroën ZX. However, the car is larger than the 306 in every direction.
The 307 continued the company's styling first seen on the Peugeot 206 and Peugeot 607. With upswept front lights and a steeply rising bonnet leading to a highly sloped windscreen (and the upright rear doors first seen on the 206), the 307 departed from the Pininfarina-designed themes employed on the previous two generations of Peugeots, as introduced with the Peugeot 205, and ending with the (evolutionary) Peugeot 406.
Its height is 1510mm (59.4in), which is in the middle of the spectrum between small family cars (between 1400 and 1450mm) and compact MPVs (between 1600 and 1650mm). Some consider the 307 as a low compact MPV rather than a tall small family car, because of its height and profile.
At launch, the 307 was launched as a 3- and 5-door hatchback, though in 2002 the 307 range was expanded with the introduction of two estates, called the 307 Break and 307 SW. Externally they are almost identical, with the exception that the SW version has silver roof bars and a 3/4 length panoramic glass roof as standard equipment. Internally though, the 307 Break is a conventional estate, while the SW features an optional third row of removable seats so it is more flexible due to its MPV-like configuration. The SW exists because Peugeot did not develop a compact MPV spin-off as Citroën did with the Xsara Picasso, instead preferring to offer a more flexible version but maintaining the style and road manners of an estate.
The 307 CC, a cabriolet with a retractable hardtop, was launched in 2003 to compete against the new European coupé cabriolets.
In 2004, a four-door saloon version of the 307 was launched in China. The 307 is produced for the Chinese market by the Dongfeng Peugeot-Citroën Automobile, a joint venture with the PSA Group. This model is also built in Argentina since early 2004.