Since you always want to copy the 15 rows after each other, and in your example the number "Numéro de Compteuer" always appear at 2, 16, 30 (each 15 step) you could skip the search function and just copy every 15th row and what is below.
You need to define where you want to paste your copied range... I just took Sheet2.
Something to start with:
Sub test()
Dim LastRow As Long
Dim sh As Worksheet
Dim sh2 As Worksheet
Dim X As Long
Set sh = Sheets("Sheet1") 'Define sheet to copy from
Set sh2 = Sheets("Sheet2") 'Define sheet to copy to
LastRow = sh.Cells(Rows.Count, 2).End(xlUp).Row 'Find last row to copy from
For X = 2 To LastRow Step 15 'Jump 15 step each time (since you are interested in every 15 row)
If Worksheets("Sheet1").Cells(X, 2) <> "" Then 'If cell is empty then
Range(sh.Cells(X, 2), sh.Cells(X + 14, 2)).Copy 'Copy the range, where 15 rows downward will be copied each time
sh2.Range(sh2.Cells(X, 5), sh2.Cells(X + 14, 5)).PasteSpecial xlPasteValues 'Paste somewhere
End If
Next
Application.CutCopyMode = False
End Sub