admin/tabs/AdminAddresses.php
=> remove «style="text-transform: uppercase;"» on:
<input type="text" size="33" name="lastname" value="’.htmlentities($this->getFieldValue($obj, ‘lastname’), ENT_COMPAT, ‘UTF-8’).’" style="text-transform: uppercase;" > <sup>*</sup>

admin/tabs/AdminCustomers.php
=> remove «style="text-transform: uppercase;"» on:
<input type="text" size="33" name="lastname" value="’.htmlentities($this->getFieldValue($obj, ‘lastname’), ENT_COMPAT, ‘UTF-8’).’" style="text-transform: uppercase;" > <sup>*</sup>

admin/tabs/AdminEmployees.php
=> remove «style="text-transform: uppercase;"» on:
<input type="text" size="33" name="lastname" value="’.htmlentities($this->getFieldValue($obj, ‘lastname’), ENT_COMPAT, ‘UTF-8’).’" style="text-transform: uppercase;" > <sup>*</sup>

classes/Address.php
=> find this line and change to this: «$fields[‘lastname’] = pSQL($this->lastname);»

classes/Customer.php
=> find this line and change to this: «$fields[‘lastname’] = pSQL($this->lastname);»

classes/Employee.php
=> find this line and change to this: «$fields[‘lastname’] = pSQL($this->lastname);»

http://www.prestashop.com/forums/viewthread/30451/general_discussion/return_the_surname_from_the_db_as_capitalize_text

It's annoying that the last names are all caps as a default in Prestashop. Here's how to fix it.

Prestashop 1.2.5 Remove Caps for Last Name

PHP