We Claim:
1. Naphtha hydrotreating process using at least three catalysts, each of said catalysts being
characterized by its "loaded specific surface area", denoted by L1, L2 and L3, respectively,
corresponding to its specific surface area by mass multiplied by its loaded density,
said process comprising three successive steps:
‐ a first step a) in the presence of the first catalyst, said first catalyst comprising a support and optionally an active phase, said active phase containing at least one Group 6 metal and preferably at least one Group 9 or 10 metal;
‐ a second step b) in the presence of the second catalyst, said second catalyst comprising a support and an active phase, said active phase containing at least one Group 9 or 10 metal and at least one Group 6 metal;
‐ a third step c) in the presence of the third catalyst, said third catalyst comprising a support and an active phase, said active phase containing at least one Group 6 metal and optionally at least one Group 9 or 10 metal;
such that:
‐ the content of Group 6 metal of the third catalyst is less than the content of Group 6 metal of said second catalyst;
‐ the ratio L1/L2 of the "loaded specific surface area" of said first catalyst to the "loaded specific surface area" of said second catalyst is greater than or equal to 1.20, preferably greater than or equal to 1.35;
‐ the ratio L3/L2 of the "loaded specific surface area" of said third catalyst to the "loaded specific surface area" of said second catalyst is greater than 1.07, preferentially greater than or equal to 1.20, more preferentially greater than or equal to 1.35.
2. Process according to Claim 1, in which said first catalyst comprises an active phase, said active
phase containing at least one Group 6 metal and preferably at least one Group 9 or 10 metal, so that:
‐ the content of Group 6 metal of said first catalyst is less than the content of Group 6 metal of said

second catalyst.
3. Process according to Claim 2, in which the active phase of the first catalyst contains at least one
Group 9 or 10 metal, so that:
‐ the content of Group 9 or 10 metal of said active phase of the first catalyst is greater than or equal to 0.5% by weight and less than 3% by weight;
‐ the content of Group 9 plus 10 metal of said active phase of the first catalyst is less than the content of Group 9 plus 10 metal of said second catalyst;
‐ the content of Group 6 metal of said first catalyst is preferably greater than or equal to 0.5% by weight and/or, preferably, less than or equal to 6% by weight.
4. Process according to Claim 2, in which the active phase of the first catalyst contains at least one
Group 9 or 10 metal, so that:
‐ the content of Group 9 or 10 metal of said first catalyst is greater than or equal to 3% by weight and less than or equal to 9% by weight;
‐ the content of Group 9 plus 10 metal of the first catalyst is greater than the content of Group 9 plus 10 metal of said second catalyst;
‐ the content of Group 6 metal of said first catalyst is preferably greater than 6% by weight, more preferably greater than or equal to 7.5% by weight, and/or preferably less than or equal to 10% by weight, more preferably less than or equal to 9.5% by weight.
5. Process according to Claim 1, in which said first catalyst consists of a support without an active phase.
6. Process according to one of the preceding claims, in which the active phase of the third catalyst contains at least one Group 9 or 10 metal, so that:
‐ the content of Group 9 plus 10 metal of the third catalyst is less than the content of Group 9 plus 10 metal of said second catalyst.
7. Process according to one of the preceding claims, in which the liquid hourly space velocity of the

first step is less than or equal to 20 times the overall liquid hourly space velocity, preferably less than or equal to 10 times and/or greater than or equal to 1.33 times the overall liquid hourly space velocity, preferably greater than or equal to 1.6 times said velocity.
8. Process according to one of the preceding claims, in which the liquid hourly space velocity of the second step is less than or equal to 4 times the overall liquid hourly space velocity, preferably less than or equal to 2.5 times and/or greater than or equal to 1.33 times the overall liquid hourly space velocity.
9. Process according to one of the preceding claims, in which the liquid hourly space velocity of the third step is greater than or equal to 5 times the overall liquid hourly space velocity, preferably greater than or equal to 6.66 times and/or less than or equal to 20 times, and preferably less than or equal to 14.29 times the overall liquid hourly space velocity.

10. Process according to one of the preceding claims, in which the first and/or third catalyst is chosen from a catalyst containing molybdenum alone, or nickel and molybdenum, or cobalt and molybdenum, or nickel and cobalt and molybdenum.
11. Process according to one of the preceding claims, in which the second catalyst is chosen from a catalyst containing nickel and molybdenum, or cobalt and molybdenum, or nickel and cobalt and molybdenum.
12. Process according to one of the preceding claims, in which said naphtha comprises hydrocarbons comprising from 10 to 50 000 ppm by weight of one or more sulfur‐based compounds.
13. Process according to one of the preceding claims, in which said naphtha comprises a cracked naphtha feedstock, alone or as a mixture with other naphtha feedstocks.
14. Naphtha hydrotreating process, comprising a hydrotreating process according to one of the preceding claims, producing a hydrodesulfurized naphtha,
said process comprising the following preliminary steps:
‐ an optional step of hydrogenation of diolefins, producing a naphtha with a reduced content of diolefins;
‐ one or more optional steps of separation and/or heating and/or cooling;

and the following additional steps:
‐ a step of separation of at least part of the hydrodesulfurized naphtha to remove H2S and optional production of an LPG fraction and/or of an uncondensable stream;
‐ an optional step of separating the hydrodesulfurized naphtha into at least two naphtha fractions.
15. Naphtha hydrotreating unit comprising a reaction section containing at least three catalysts, said catalyst being loaded onto first, second and third successive layers of catalyst and each of said catalysts being characterized by its "loaded specific surface area", denoted by L1, L2 and L3, respectively, corresponding to its specific surface area by mass multiplied by its loaded density,
said naphtha feedstock being successively placed in contact, in the presence of hydrogen, in said reaction section with:
‐ the first layer of catalyst, said first catalyst comprising a support and optionally an active phase, said active phase containing at least one Group 6 metal and preferably at least one Group 9 or 10 metal;
‐ the second layer of catalyst, said second catalyst comprising a support and an active phase, said active phase containing at least one Group 9 or 10 metal and at least one Group 6 metal;
‐ the third layer of catalyst, said third catalyst comprising a support and an active phase, said active phase containing at least one Group 6 metal and preferably at least one Group 9 or 10 metal;
such that:
‐ the content of Group 6 metal of the third catalyst is less than the content of Group 6 metal of the second catalyst;
‐ the ratio L1/L2 of the "loaded specific surface area" of said first layer of catalyst to the "loaded specific surface area" of said second layer of catalyst is greater than or equal to 1.20, preferably greater than or equal to 1.35;
‐ the ratio L3/L2 of the "loaded specific surface area" of said third layer of catalyst to the "loaded specific surface area" of said second layer of catalyst is greater than 1.07, preferentially greater than or equal to 1.20, more preferentially greater than or equal to 1.35.

16. Naphtha hydrotreating unit according to Claim 15, in which the first, second and third layers of catalyst are loaded into at least one reactor operating with a fixed catalytic bed and in axial flow, notably a single reactor.