New mid-sizer to sport slimline tail-lights when it lobs in Paris.

BMW has released another teaser for its upcoming 2019 3 Series, this time using video of the production line to offer a peek at its rear three-quarter.

Set for a Paris motor show reveal, the new 3er wades into battle with the just-updated Mercedes-Benz C-Class and Audi A4. It'll be built on a variation of the CLAR platform underpinning the 5 and 7 Series, for weight savings of around 55kg over the current car.

It'll have a centre of gravity 10mm lower than before and the track is 30mm wider, while overall torsional stiffness is up 25 per cent. All of those are good things.

Four-cylinder power will be the staple, but an inline six will be offered at some point in the car's life as part of the usual hybrid, petrol and diesel powertrain spread. Expect an eight-speed ZF automatic to be standard in the vast majority of variants.

As we learned on a prototype drive of the new 3 Seriesthe M Sport package on the 330i brings 19-inch wheels, bigger brakes, an electronically-controlled limited slip differential, and sport-specific suspension bushings.

On that prototype drive, they were described as "almost as miraculous as magnetorheological dampers in their ability to quell body motion".

Inside, the 3 Series will get the latest BMW OS7.0 infotainment system and digital display. Voice control in a similar vein to MBUX will be coming with an over-the-air update early next year.