Database to classify documents (.pdf, .doc)

The actual website has a "Documents" section. I have joined a screenshot. He would like a search engine to search trough documents. I was thinking of creating a database for all documents. There would be 6 major sections to classify documents. I was also thinking of the possiblity to assign tag words (keywords) for each documents. I want the search engine to search keywords assign by the admin but also into documents text content. The documents will be PDF and Microsoft Word. The front-end of the webpage would be an advanced search engine that give possibility to search by the 6 major categories and also keywords. I have joined a screenshot of what I see . The keywords define by the admin (tag) would be prioritized over the document text content. We would list results in the section: first section are results from keywords (tag) and second, results from text content. I want an admin interface that let the admin to add documents, assign title, description and keywords to each document. I want the admin to be able to add/edit/delete documents entries. Also, it would be great to be able to create new categories. If you speak French, c'est encore mieux!