Find duplicate files in Linux
Please be careful with the indentation because it looks like there are different number of spaces for different indentation depths and it looks very weird.

Minor improvements:

Repetition

 md5 = hashlib.md5()
 path = same_size[size][i]
 md5 = hashlib.md5()


I am almost sure there is no reason to repeat md5 = hashlib.md5() twice.

"Native" iteration

while i &lt; len (same_size[size]):
 # Hash file content with read buffer
 md5 = hashlib.md5()
 path = same_size[size][i]
 ...
 i=i+1


You are iterating over all the files with the given size:

for path in same_size[size]:
   ...


In general in Python you can use for x in list_ to iterate over all items in any collection.

Zero length automatically skipped

if len (same_size[size]) &gt; 1:


If you ask python to iterate over a zero length collection nothing happens, so you can remove this line as it does nothing but increases indentation and line count.

edit: No @miracle173 correctly noted that this is an efficiency gain to skip files of which there is only one of a certain size so it cannot be skipped.

Default dict to simplify logic

    if file_size not in same_size:
     same_size[file_size] = list([path])
    else:
     same_size[file_size].append(path)


Not tested, but using a defaultdict you can avoid the branch and only use append.

Same size?

Are you sure you need to calculate also the size in order to check if two files are equal? Isn't the hash enough?