Over the period 1994-2005, industrial production prices changed on average every six months, and prices for company services every twelve months. This rhythm varies from one sector to the next: energy prices last on average a little over two months while those for capital goods last just under eight months. Furthermore, price changes are relatively modest in scale for all production prices. Falls and rises amount to around 4% on average. A little over 40% of price changes are falls, and there is no bias in the distribution of price change levels except in company services. In this latter sector, changes are less frequent, but more marked and more likely to be rises. The determiners of price changes are mainly calendar effects (periods when contracts are signed between companies) and general changes in production prices. To a lesser extent, the position in the sector's economic cycle and the cost of raw materials also have an influence. The structure of the market in the sector also seems to act as a shock absorber: in the most concentrated sectors, prices are less reactive to economic changes. General changes in production prices, which vary greatly over the period in question, may be the result of a combination of several microeconomic factors: the general level of price increases (or falls) because companies change their prices more often (or less often) or the result of price rises which are on average more significant (or less significant) than in the past. It seems that general price changes are more determined by the relationship between the number of price rises and the number of price falls than by the scale of these rises or falls.