Solution : https://service.sap.com/sap/support/notes/89089 (SAP Service marketplace login required)
Key words : 
prerequisites hr legal change patches, additional key words lcp hr, legal change patch collection cd 3, return code sy-subrc = 0, return code sy-subrc = 4, choose 'basic functions' -> 'end, hr legal change patches, 'sap legal change patches', 'utilities' -> 'text display' -> 'sapscript', 'tools' -> 'business engineering' -> 'customizing'
Related Notes : 
       
| 334872 | Separation LCPs HR/Hot Packages in Release 4.0B | 
| 155671 | @3B@Documentation LCP Collections in 3.1H | 
| 151670 | @3B@Documentation LCP collections in 4.5B | 
| 136076 | HR US Release note for 4.0B | 
| 135041 | Separation LCPs HR / Hot Packages as of Rel. 4.5B | 
| 125888 | HR-US: LCP Release Notes for Year-End 1998 | 
| 122204 | @3B@Documentation LCP Collections for Release 3.0F | 
| 120120 | Documentation update for VETS-100 and EEO-1 reports | 
| 119825 | @19@OCS: Changing a 3.0F system to LCP HR | 
| 119152 | Tax Reporter IMG update | 
| 105475 | @3B@Documentation LCP Collections to 3.1I | 
| 104465 | Contents of and applying HR LCPs 4.0B | 
| 104463 | Contents and applying HR LCPs 3.1I | 
| 104128 | @3B@Documentation LCP Collections to 4.0B | 
| 100470 | HR US: Legal changes 1997/98 - tax reporter | 
| 98805 | @3B@Additions documentation as of 3.1H/L2 | 
| 97799 | HRMS US: Legal changes 1997 -> 1998 | 
| 97630 | OCS: Familiar problems with patches 3.1H-4.0B | 
| 97620 | OCS Info: Overview of Important OCS Notes | 
| 87432 | Contents of and applying HR LCPs 3.1H | 
| 86241 | Legal Change Patches / Support Packages for HR | 
| 83458 | @19@OCS Info: Patch download from SAP Service Marketplace | 
| 73510 | Problems during upgrade of patched source releases |