By Ben Hall in Paris

France is to reduce its armed forces by almost a fifth and close scores of bases under a defence overhaul that will increase spending on spy satellites, cruise missiles and transport.

Long-awaited defence legislative proposals – to be launched on Tuesday by President Nicolas Sarkozy – will aim to modernise Europe’s second most powerful military, creating slimmer but more deployable forces as part of a 15-year national security strategy that stretches beyond conventional territorial defence to deal with terrorism, missile strikes and natural disasters.

France will reduce its army to 88,000 deployable troops – roughly akin to British land forces – but will increase spending on technology and intelligence. In total some 54,000 jobs across all services are due to go.

The document marks a change of direction in several respects from existing French defence doctrine. It confirms France’s intention fully to rejoin Nato’s integrated military command structure, while maintaining complete control over its nuclear strike capability. “This differentiation no longer has its raison d’être,” said an official who helped draw up the white paper.

In return for rejoining Nato’s military command, France will press ahead with plans to boost the European Union’s role in defence.

Intelligence and anticipation of threats will play a greater role with spending on satellite technology to double to €700m ($1.08bn, £552m) a year. From 2015 France will start to put in place a ballistic missile detection system using infra-red sensors on satellites and long-range radar to be fully operational by 2020. It wants other countries to join in the project.

The white paper also redraws the map of possible French military intervention along an axis of potential trouble-spots running from the north Atlantic to the Indian Ocean, stretching from west Africa to south Asia.

The new policy was drawn up against tight spending restraints. As well as cuts in manpower over seven years, the government will seek to close many of the 470 military installations around the country at the risk of a furious political backlash, including from within Mr Sarkozy’s own party.

The government will use cost savings to increase spending on procurement from €15.5bn a year to an average of €18bn a year from 2009-2020.

Priorities will include developing France’s own cruise missile, a fleet of six submarines to fire them, and armoured personnel carriers for the army,

However, a decision on whether to build a second aircraft carrier at an estimated cost of €2.8bn has been put back until 2011 and some other large procurement programmes could also be delayed or scaled down.

Defence spending, which in 2008 amounts to €30bn or 2.3 per cent of gross domestic product, will be frozen in real terms until 2012, and will then rise by 1 percentage point ahead of inflation until 2014.

The defence overhaul will also trigger a transformation of France’s military links with its former colonies in Africa, with all 30 or so defence accords open to review and many expected to be scrapped. Instead of bilateral ties, which have often obliged Paris to intervene militarily on behalf of dubious regimes, France will favour multilateral solutions and intervention alongside European partners.