Although the authenticity of the images cannot be confirmed, above is the allegedly design of the front end of the next smart phone which is developed by Microsoft. It was published by French website NowhereElse. The photo displayed a large handset with thin bezels and possibly a new flagship (which of course, it is just a wild guess).
From the first impression, there is a speculation that it might be the design of the next model to the Lumia icon / Lumia 930. Assuming that this is correct, there is a possibility whereby it can turns out to be a nice looking smart phone.
On side note, unfortunately there are some rumours that Microsoft could drop Nokia branding from its future Lumia smartphones series. The timeline is by the end of the year. Although this rumours are yet to be confirmed. If it is going to be happened in the future, then the recently announced Lumia 830 and Lumia 730/735 could be the last Nokia-brand Windows phone ever. The Nokia brand would also be disappear from the electronic shop whereas the Lumia range project will still continued.