plates were introduced in 1963 but only became compulsory on new cars in 1993. The new plates had to be white on the front and yellow on the rear until 2007, when white rear plates were allowed. Numbering The FNI format was chronological, as is the SIV system. It was also regional, which means that it evolved independently in each . Registration plates contained from 4 to 8 alphanumeric characters split into three parts by spaces. The first space could be omitted on registration plates issued after 1996. First part: one to four numbers; Second part: one to three letters; Third part: the code for départments. Numbering went as follows: numbers evolved first, starting from 1, until they reached 999. Then letters evolved. The first car registered in Paris had a 1 A 75 car plate, and the second one 2 A 75. Once 999 A 75 had been reached, the following car was registered under 1 B 75. The format would have been exhausted in Paris once 999 ZZZ 75 had been reached. The following chronology summarises the numbering system. Most of the chose to have four numbers on their plates once the letters reached QA, in order to have more combinations available. The "00" at the end stands for the geographical code. 1 A 00 to 999 Z 00; 1 AA 00 to 999 PZ 00; 1 QA 00 to 9999 ZZ 00; 1 AAA 00 to 999 ZZZ 00. Numbers from 1 to 10 and numbers identical to the code (such as 24 VQ 24) were not used after 1976. As with the SIV system, The letters I and O were never used because they could be confused with other characters, like 1 and 0. U was excluded as well in 1984, similar to the letter V, but some départements issued registration plates containing that letter until 1991. The letter O was exceptionally used on official cars at the 1992 Winter Olympics in Albertville. Such cars had registration plates with figures between 1 JO 73 and 9999 JO 73. "JO" stands for Jeux olympiques while "73" is the code for Savoie where the games took place. Offensive letter combinations, for instance SS, PD, PQ, QQ, KK or WC, were avoided by some either because of historical reasons or because they sound vulgar to French speakers. In the same way, Haute-Garonne did not deliver car plates with "AZF"