In Paris, there have been warnings and increased security for weeks. There are always military patrols inside the rail stations though you will see the vigipirate teams around the city much more often than in the past. (Adding large decals to the trucks probably helped make them even more noticeable as well.) The Guardian:
Fears of a terrorist attack in Europe were heightened today after travel alerts were issued by both Washington and London, with the US state department warning that public transport systems and tourist attractions could be targeted, and Britain increasing the threat level for travel to Germany and France.
The US alert made no mention of a specific European country, but pointed the finger at al-Qaida and its affiliates and suggested both official and private targets could be in terrorists' sights.
The move follows speculation that al-Qaida was planning a "commando-style" attack similar to the 2008 Mumbai massacre, in which 166 people were killed.
