how to find marginal profit calculus Like most of the developed countries, France's car market also belongs to the mature market, tend to be saturated, most new car sales are no longer a first-time buyers of consumer is bought, is more of a used car. Subject to regional economy, the cost of living, and the influence of cultural background, etc, the French are more keen to sta domestic car, in French, so we will find that their vehicle seems to is not match with the national economic development level, and it is precisely the characteristics of these European developed countries have in common, they did not imagine the high to the requirement of cars, more practical. Psa Peugeot Citroen sold 51,188 cars in France in 2014, down 2.2% from a year earlier, according to data from the auto industry. Sales at Renault also fell 0.4 per cent year on year to 37,898 units. In addition, Volkswagen, ford, Toyota and most other car companies suffered declines in France in 2014, and France's current car market is not expected to sell well. According to the engine displacement, divided into a miniature (1 liter), light level sedan (1-1.6 liters), intermediate (1.6-2.5 litres), senior sedan (2.5 4 liters), limousine (4 liters). Frances O 'grady, chief secretary of the UK federation of industry and industry, said: "this suggests that brexit uncertainty has damaged the household budget. Work and living standards must be a priority in determining the best choice for brexit. The government should maintain a single market membership at the negotiating table. " Britain has a long history of motor vehicle development, and the world's leading enterprises, universities, motor racing industry and autonomous projects have the strength to realize the transformation and development. Professional knowledge and forward-looking thinking are the unique advantages of developing core automotive technology in the UK.